Help me with Percent word problems

Answer:

Step-by-step explanation:

a) The mean of a normal distribution is also the median. Half the population will have values above the mean. Half of 200 is 100, so ...

... 100 students will have grades above 70%.

b) 84% is 14% above the mean. Each 7% is 1 standard deviation, so 14% is 2 standard deviations above the mean. The empirical rule tells you 95% of the population is within 2 standard deviations of the mean, so about 5% of students (10 students) got grades higher than 84% or lower than 56%. The normal distribution is symmetrical, so we expect about 5 students in each range.

... about 5 students will have grades above 84%.

1. The number of students who received a grade greater than 70% is about 100.

2. The number of students who got a grade higher than 84% is about 195.

To find the number of students who received a grade greater than 70%,

you need to calculate the area under the normal distribution curve to the right of 70%.

Similarly, to find the number of students who got a grade higher than 84%,

you need to calculate the area under the normal distribution curve to the right of 84%.

You can use the z-score formula to convert the given grades to z-scores, then look up the corresponding areas in the standard normal distribution table.

For a grade of 70%:

[tex]\[ Z = \frac{X - \mu}{\sigma}[/tex]

[tex]= \frac{70 - 70}{7}[/tex]

= 0

For a grade of 84%:

[tex]\[ Z = \frac{X - \mu}{\sigma}[/tex]

[tex]= \frac{84 - 70}{7}[/tex]

[tex]\approx 2[/tex]

Then, you look up the corresponding areas in the standard normal distribution table:

Now, to find the number of students:

Students with grades greater than 70%:

Number of students = Total students × Area to the right of 70%

= 200 × (1 - 0.5000)

= 200 × 0.5000

= 100

Students with grades higher than 84%:

Number of students = Total students × Area to the right of 84%

= 200 × (1 - 0.0228)

≈ 200 × 0.9772

≈ 195

So, the number of students who received a grade greater than 70% is about 100, and the number of students who got a grade higher than 84% is about 195.

Hi there! :)

Answer:

Subtract 43 from 20 raised to the 7th power; then multiply by 3. The answer is: 3,839,999,871

Step-by-step explanation:

"Subtract" means to take away a number from another.

" 20 raised to the 7th power" is the same thing as 20 exponent 7: [tex]20^{7}[/tex]

SO, you want to take away 43 from [tex]20^{7}[/tex] and then multiply the answer by 3:

([tex]20^{7}[/tex] - 43) × 3

[tex]20^{7} =[/tex] 1,280,000,000

(1,280,000,000 - 43) × 3

1,280,000,000 - 43 = 1,279,999,957

1,279,999,957 × 3

1,279,999,957 × 3 = 3,839,999,871

There you go! I really hope this helped, if there's anything just let me know! :)

Answer:

I got 3839999831

Step-by-step explanation:

So 20^7(calculator), then subtract and mult

Answer:

86%

Wouldn't you just be finding the ratio of pennies to Canadian.

Step-by-step explanation:

The amount of pennies to Canadian pennies are 13/15

And the amount of Canadian pennies to pennies are 2/15

If you pick a random penny out of your pocket it would be a larger possibility to get the regular pennies.

So the ratio would be I think:

There would be an 86% more chance of grabbing a regular penny than the 13% chance of getting a Canadian penny.

The probability of not picking a Canadian penny from a total of 15 pennies, with 2 being Canadian, is 13/15 or approximately 86.7%.

To find the probability of not picking a Canadian penny (P(not Canadian)), we first consider the total number of non-Canadian pennies. Since there are 15 pennies in total and 2 of them are Canadian, there must be 15 - 2 = 13 non-Canadian pennies.

The probability of an event is defined as the number of favorable outcomes divided by the total number of possible outcomes. Therefore, the probability of picking a non-Canadian penny is:

P(not Canadian) = Number of non-Canadian pennies / Total number of pennies

P(not Canadian) = 13 / 15

This simplifies to approximately 0.867, or 86.7% when expressed as a percentage.

B. MN/LN = RS/QR

ΔQRS ~ ΔLMN so corresponding segments are ...

Corresponding segments have the same ratio. So, ...

... LM/LN = QR/QS . . . . does not match A

... MN/LM = RS/QR . . . . matches B

... LM/MN = QR/RS . . . . does not match C

... MN/LM = RS/QR . . . . does not match D

Answer:

[tex]\ast=16a^2[/tex]

Step-by-step explanation:

Use formula for  a square of a sum:

[tex](x+y)^2=x^2+2xy+y^2.[/tex]

Note that

Then instead of * should be the square of the term 4a that is [tex](4a)^2=16a^2.[/tex]

Then

[tex]16a^2+56a+49=(4a+7)^2.[/tex]

To complete the pattern in the expression ∗ +56a+49 to make it a square of a sum or a difference, we can use the formula for (a+b)² as a guide. If 49 is b² and 56a is 2ab, the missing part would be a². On solving, we find that the value of a² is 16a².

The subject of this question is finding a monomial such that the given expression can be rewritten as a square of a sum or a difference. The expression is ∗ +56a+49. We can think of the square of a sum or a difference as the result of the formula (a+b)² = a² + 2ab + b² which gives a hint that we can structure our expression in a similar way.

Let's rearrange the given expression a bit using this hint. If we look at 49, it is equal to 7². This could be our b². Additionally, 56a can be written as 2*7*a or 2ab. So the missing part would be a² which completes the pattern of the formula.

To find the value of a², we need to know the value of a. Here's where 56a comes into play. It is 2ab (or in this case, 2*7*a). Solving this equation for a, we get a=4. So, a²=16. Therefore, the monomial that completes the pattern in the expression is 16a².

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Answer:

Step-by-step explanation:

Given:

Length (l) = 12 cm

Width (w) = 4 cm

Perimeter of the rectangle = 2(l + w) units

P = 2(12 + 4)

P = 2 (16)

P = 32

Answer:

B. -2

Step-by-step explanation:

We have been given an expression [tex]\frac{P}{3Q}[/tex] and we are asked to evaluate our expression, when P=-24 and Q=4.

Let us substitute P=-24 and Q=4 in our given expression.

[tex]\frac{-24}{3*4}[/tex]

Let us multiply 3 by 4.

[tex]\frac{-24}{12}[/tex]

[tex]-\frac{24}{12}[/tex]

Upon dividing 24 by 12 we will get,

[tex]-\frac{24}{12}=-2[/tex]

Therefore our expression simplifies to -2 and option B is the correct choice.

Answer:

The greatest value is q-n

The smallest value is n-q

q is closest to 0

Step-by-step explanation:

The further to the left we go, the more negative it gets

n < q

from looking at the graph

n<q

Subtract q from each side

n-q < q-q

n-q < 0

This is less than 0

Now subtract n from each side

n<q

n-n < q-n

0 < q-n

This is greater than 0

Lets compare n-q  and q

n = -4

q = -1

n-q  = -4 --1 = -4 +1 = -3

-3 < -1

n-q < q

Lets look at q-n

-1 --4

-1 +4 = 3

q is closer to 0 than q-n

The greatest value is q-n

The smallest value is n-q

q is closest to 0

Answer:

D. 13

Step-by-step explanation:

Multiply the given equation by 39x/27:

... x = 9·39/27 = 39/3

... x = 13

______

The usual approach

You may have learned to "cross multiply" to eliminate fractions. That means you multiply by the product of the denominators, 39x:

... 9·39 = 27x

Now, you divide by the coefficient of x, which is 27.

... 9/27 · 39 = x = 39/3 = 13 . . . . . . in the end, the same as above

To find the unknown value in the given proportion, we can cross-multiply and solve for the variable.

To find the unknown value in the proportion 9/x = 27/39, we can cross-multiply. Cross-multiplying means multiplying the numerator of the first fraction with the denominator of the second fraction, and multiplying the denominator of the first fraction with the numerator of the second fraction. So, we have 9 * 39 = 27 * x.

Now, we can solve for x by dividing both sides of the equation by 27. So, x = (9 * 39) / 27. Simplifying further, we have x = 351 / 27 = 13.

Therefore, the unknown value in the proportion is 13. Hence, the correct option is D.

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C. 75°

The sum of the three angles is 180°, as it is for the angles in any triangle.

35° + 70° + x° = 180° . . . . an equation expressing the relationship of the angles

x° = 180° -35° -70° . . . . . subtract 35° and 70°

x° = 75°

D. There are no solutions

First inequality:

... -16 ≥ 8x . . . . . . . add 8x-60 to the inequality

... -2 ≥ x . . . . . . . . divide by 8

Second inequality:

... -8 < 4x . . . . . . . . add 4x-58 to the inequality

... -2 < x . . . . . . . . . divide by 4

The problem statement requires a solution satisfy both conditions on x. The two solution sets are disjoint (have no points in common), so ...

... there are no solutions.

A)

B) It is a matter of definition: speed = distance/time. Speed is proportional to distance and inversely proportional to time.

Speed is defined as the ratio of distance to the time required to cover that distance:

... speed = distance/time

Solving this relation for time, we have ...

... time = distance/speed

a) For each of the modes of transportation, we can find the time by using this relation.

... motorcyle: (150 km)/(75 km/h) = 2 h

... bus: (150 km)/(60 km/h) = 2.5 h

... truck: (150 km)/(50 km/h) = 3 h

... bicycle: (150 km)/(20 km/h) = 7.5 h

b) For a given distance, speed and time are inversely related as a matter of definition.

Answer:

4x-2=0

5x-3=0

Step-by-step explanation:

Assuming your target boxes are (-12x +36) and (8x -24), here are the classifications of the expressions with parentheses.

-3(4x + 12) = -12x -36 (neither)

-4(3x -9) = -12x +36

4(2x - 6) = 8x -24

-4(-2x - 6) = 8x +24 (neither)

3(-4x +12) = -12x +36

2(4x - 12) = 8x -24

_____

The distributive property applies:

... a(b+c) = ab +ac

Same signs multiply to give positive. Different signs multiply to give negative.

Expressions like -3(4x + 12), -4(3x -9), and 3(-4x +12) are equivalent to -12x + 36 while 4(2x - 6) and 2(4x - 12) are equivalent to 8x - 24. The expression -4(-2x -6) is not equivalent to others.

The question is asking to categorize the expressions whether they are equivalent or not. Two expressions are equivalent if they have the same value for all values of their variables. Let's evaluate each expression:

So we see that -3(4x + 12), -4(3x -9), and 3(-4x +12) are equivalent to -12x + 36, while 4(2x - 6) and 2(4x - 12) are equivalent to 8x - 24. The expression -4(-2x -6) doesn't match any other expression.

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C). The function is linear because it decreases at a constant rate.

y changes by -1 every time x changes by +2. When the rate of change is constant, the function is linear.

Answer:

Length of wire = 50 ft

Step-by-step explanation:

In the figure below AB is the telephone pole and C is the point on the ground where wire is anchored.

so we have

AB= 45 ft

∠ACB= 64°

Let is assume the length of the wire be x ft

now in Δ ABC

[tex]sin C = \frac{AB}{AC}[/tex]

we can plug AB= 45, ∠C= 64°and AC=x

so we have

[tex]sin(64)[/tex]°[tex]=\frac{45}{x}[/tex]

[tex]xsin(64)[/tex]°[tex]=45[/tex]

[tex]x=\frac{45}{sin(64)}[/tex]

now we have sin 64°=0.8988

[tex]x=\frac{45}{0.8988}[/tex]

[tex]x=50.07[/tex] ft

rounding to nearest foot

x= 50 ft

Final answer:

To find the length of the wire attached to a telephone pole at a 64-degree angle, we use the tangent function, resulting in an approximate wire length of 22 feet to the nearest foot.

Explanation:

The question asks how long a wire is if it's attached to the top of a 45-foot telephone pole and anchored to the ground, with an angle of elevation of 64 degrees.

To solve this, we can use trigonometry, specifically the tangent function, because we know the opposite side (height of the pole) and are trying to find the hypotenuse (length of the wire).

The tangent of an angle in a right triangle is the opposite side divided by the adjacent side. In this scenario, the angle of elevation is 64 degrees and the opposite side (height of the telephone pole) is 45 feet.

To find the length of the wire (hypotenuse), we use the formula: length of wire = opposite side / tan(angle), which translates to length of wire = 45 / tan(64 degrees).

Using a calculator, we find that tan(64 degrees) is approximately 2.05.

Therefore, the length of the wire is approximately 45 / 2.05, which equals about 21.95 feet.

To the nearest foot, the wire would be 22 feet long.

(2π-5) radians ≈ 1.2831853 radians

The reference angle is the magnitude of the acute angle made with the x-axis. The value of θ is greater than 3π/2, so the reference angle is ...

... θ' = abs(θ -2π) = 2π-5 . . . . radians

Answer:

Add 78 to 54 to get 132 total patrons, then divide the number of females into the total number of patrons. Therefore, 78/132 = .5909 = 59%

Step-by-step explanation:

Answer:

Thats simple!

Step-by-step explanation:

G.o.o.g.l.e.

There is an infinite number of numbers between 1 and 1.01 on the number line. The correct answer should theoretically be: 1 < n < 1.01.

Answer:

3(t+2)

Step-by-step explanation:

As with any problem involving division of fractions, you can invert the denominator and multiply.

Your knowledge of the factoring of the difference of squares helps. If that doesn't work for you, you can always use synthetic division or polynomial long division to find the quotient of (t^2-4) and (t-2).

[tex]\displaystyle\frac{\frac{4t^2-16}{8}}{\frac{t-2}{6}}=\frac{4(t^2-4)}{8}\cdot\frac{6}{t-2}\\\\=\frac{3(t+2)(t-2)}{t-2}=3(t+2)[/tex]

Answer:

31.25 %

Step-by-step explanation:

The fraction bar also means divide:

5 / 16

=

5 Divided By 16

=

0.3125

0.3125 * 100

= 31.25

- I.A -

The fraction 5/16 is converted to a percent by dividing 5 by 16 and then multiplying the result by 100, which equals 31.25%.

To convert the fraction 5/16 into a percent, we want to know how many parts out of 100 this fraction represents.

A percent is a way of expressing a fractional amount as a part of 100.

To do this, we can set up a proportion or multiply the fraction by 100.

So, we take 5 divided by 16 and then multiply the result by 100.

Doing the math:

= (5 / 16) x 100

= 0.3125 x 100

= 31.25%.

Therefore, the fraction 5/16 expressed as a percent is 31.25%.

Answer:

A, D, and E

Step-by-step explanation:

So the function 350-45t for t hours means that he reads 45 pages every hour. So, going from 11 AM to 1 PM is two hours. Since his reading pace doesn't change, we just have to look for an answer that has a difference of two answers. The only answers that have a difference of two hours are A, D, and E.

To find the time periods during which Marco reads the same number of pages as he reads between 11 a.m. and 1 p.m., we need to solve the equation P(t) = 350 - 45t for t using the value of 260 pages read between 11 a.m. and 1 p.m. The time periods are from 9 a.m. to 11 a.m., and from 1:30 p.m. to 3:30 p.m.

To find the time periods during which Marco reads the same number of pages as he reads between 11 a.m. and 1 p.m., we need to determine the values of t that make P(t) = 350 - 45t equal to the number of pages read between 11 a.m. and 1 p.m. which is 350 - 45(2) = 260 pages.

Substituting this value into the equation, we get:

P(t) = 350 - 45t = 260

Solving for t, we have:

t = (350 - 260) / 45 = 2

So, Marco reads the same number of pages during the time period from 9 a.m. to 11 a.m., and also during the time period from 1:30 p.m. to 3:30 p.m.

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∠BDC and ∠AED are right angles

Because ∠C ≅ ∠C, the additional bit of information above can be used to show AA similarity.

____

None of the other offered choices says anything about both triangles. In order to show similarity, you need information about corresponding parts of the two triangles. Information about one triangle alone is not sufficient.

Answer:

I think it's A. ∠BDC and ∠AED are right angles

Step-by-step explanation:

I hope this helps.

Answer:

The graph shows that typically students with more hours of sleep(independent) had higher test scores (dependent)

Step-by-step explanation:

QUESTION 1a

The given polygon has vertices [tex]A(-2,3),B(3,1),C(-2,-1),D(-3,1)[/tex].

We plot the points and connect them to obtain the figure as shown in the attachment.

The polygon has four sides and two pairs of adjacent sides equal.

Therefore Polygon ABCD can be classified as a quadrilateral, specifically a kite.

QUESTION 1b

We can find the perimeter by adding the length of all the sides of the kite

[tex]Perimeter=|AB|+|BC|+|CD|+|AD|[/tex]

Or

[tex]Perimeter=2|AB|+2|AD|[/tex]

Recall the distance formula

[tex]d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]

We use the distance formula to find the length of each side.

[tex]|AB|=\sqrt{(3--2)^2+(1-3)^2}[/tex]

[tex]|AB|=\sqrt{(3+2)^2+(1-3)^2}[/tex]

[tex]|AB|=\sqrt{(5)^2+(-2)^2}[/tex]

[tex]|AB|=\sqrt{25+4}[/tex]

[tex]|AB|=\sqrt{29}=5.385[/tex]

Length of side AD

[tex]|AD|=\sqrt{(-3--2)^2+(1-3)^2}[/tex]

[tex]|AD|=\sqrt{(-3+2)^2+(1-3)^2}[/tex]

[tex]|AD|=\sqrt{(-1)^2+(-2)^2}[/tex]

[tex]|AD|=\sqrt{1+4}[/tex]

[tex]|AD|=\sqrt{5}=2.24[/tex]

[tex]Perimeter=2(5.1)+2(2.236)[/tex]

[tex]Perimeter=10.77+4.472[/tex]

[tex]Perimeter=15.242[/tex]

The perimeter of the kite to the nearest tenth is 15.2 units

QUESTION 1c

The area of kite ABCD is twice the area of ΔABD

[tex]Area\:of\:ABD=\frac{1}{2}\times |BD| \times |AE|[/tex]

[tex]Area\:of\:ABD=\frac{1}{2}\times 6 \times 2[/tex]

[tex]Area\:of\:ABD=6\:square\units[/tex]

Therefore the are of the kite is

[tex]=2\times 6=12[/tex]

The area of the kite is 12 square units.

QUESTION 2a

The vertices of the given polygon are

[tex]P(-3,-4),Q(3,-3),R(3,-2),S(-3,2)[/tex].

We plot all the four points as shown in the diagram in the attachment.

The polygon has one pair of opposite sides parallel and has four sides.

The polygon is a quadrilateral, specifically a trap-ezoid.

QUESTION 2b

The area of the trap-ezoid can be found using the formula

[tex]Area=\frac{1}{2}(|RQ|+|PS|)\times |RU|[/tex].

We use the absolute value method to find the length of RQ,PS and RU because they are vertical and horizontal lines.

[tex]|RQ|=|-3--2|[/tex]

[tex]|RQ|=|-3+2|[/tex]

[tex]|RQ|=|-1|[/tex]

[tex]|RQ|=1[/tex]

The length of PS is

[tex]|PS|=|-4-2|[/tex]

[tex]|PS|=|-6|[/tex]

[tex]|PS|=6[/tex]

The length of RU

[tex]|RU|=|-3-3|[/tex]

[tex]|RU|=|-6|[/tex]

[tex]|RU|=6[/tex]

The area of the trap-ezoid is

[tex]Area=\frac{1}{2}(1+6)\times 6[/tex].

[tex]Area=(7)\times 3[/tex].

[tex]Area=21[/tex].

Therefore the area of the trap-ezoid is 21 square units.

QUESTION 2c

The perimeter of the trap-ezoid

[tex]=|PQ|+|RS|+|QR|+|PS|[/tex]

We use the distance formula to determine the length of RS and PQ.

[tex]|RS|=\sqrt{(3--3)^2+(-2-2)^2}[/tex]

[tex]|RS|=\sqrt{(3+3)^2+(-2-2)^2}[/tex]

[tex]|RS|=\sqrt{(6)^2+(-4)^2}[/tex]

[tex]|RS|=\sqrt{36+16}[/tex]

[tex]|RS|=\sqrt{52}[/tex]

[tex]|RS|=7.211[/tex]

We now calculate the length of PQ

[tex]|PQ|=\sqrt{(3--3)^2+(-3--4)^2}[/tex]

[tex]|PQ|=\sqrt{(3+3)^2+(-3+4)^2}[/tex]

[tex]|PQ|=\sqrt{(6)^2+(1)^2}[/tex]

[tex]|PQ|=\sqrt{36+1}[/tex]

[tex]|PQ|=\sqrt{37}[/tex]

[tex]|PQ|=6.083[/tex]

We already found that,

[tex]|PS|=6[/tex]

and

[tex]|RQ|=1[/tex]

We substitute all these values to get,

[tex]Perimeter=6+1+7.211+6.083[/tex]

[tex]Perimeter=20.294[/tex]

To the nearest tenth, the perimeter quadrilateral PQRS is 20.3 units.

QUESTION 3a

The given polygon has vertices

[tex]E(-4,1),F(-2,3),G(-2,-4)[/tex]

We plot all the three points to the polygon shown in the diagram. See attachment.

The polygon has three unequal sides, therefore it is a triangle, specifically scalene triangle.

QUESTION 3b

We can calculate the area of this triangle using the formula,

[tex]Area=\frac{1}{2} \times |FG| \times |EH|[/tex] see attachment

We can use the absolute value method to find the length of FG and EH because they are vertical or horizontal lines.

[tex]|FG|=|-4-3|[/tex]

[tex]|FG|=|-7|[/tex]

[tex]|FG|=7[/tex]

Now the length of EH is

[tex]|EH|=|-4--2|[/tex]

[tex]|EH|=|-4+2|[/tex]

[tex]|EH|=|-2|[/tex]

[tex]|EH|=2[/tex]

The area is

[tex]Area=\frac{1}{2} \times 7 \times 2[/tex]

[tex]Area=7[/tex]

Therefore the area of the triangle is 7 square units.

QUESTION 3c

The perimeter of the triangle can be found by adding the length of the three sides of the triangle.

[tex]Perimeter=|EF|+|FG|+|GE|[/tex]

The length of EF can be found using the distance formula,

[tex]|EF|=\sqrt{(-2--4)^2+(3-1)^2}[/tex]

[tex]|EF|=\sqrt{(-2+4)^2+(3-1)^2}[/tex]

[tex]|EF|=\sqrt{(2)^2+(2)^2}[/tex]

[tex]|EF|=\sqrt{4+4}[/tex]

[tex]|EF|=\sqrt{8}[/tex]

[tex]|EF|=2.828[/tex]

The length of EG can also be found using the distance formula

[tex]|EG|=\sqrt{(-4--2)^2+(1--4)^2}[/tex]

[tex]|EG|=\sqrt{(-4+2)^2+(1+4)^2}[/tex]

[tex]|EG|=\sqrt{(-2)^2+(5)^2}[/tex]

[tex]|EG|=\sqrt{4+25}[/tex]

[tex]|EG|=\sqrt{29}[/tex]

[tex]|EG|=5.385}[/tex]

We found [tex]|FG|=7[/tex]

The perimeter of the triangle is

[tex]Perimeter=5.385+7+2.828[/tex]

[tex]Perimeter=15.213[/tex]

Therefore the perimeter of the triangle is 15.2 units to the nearest tenth

38 m/s

The formula tells you Rachael's distance to the exit decreases by 38 m for each passing second. Her speed is 38 m/s.

Answer:

38 m/ s

Step-by-step explanation:

We are given that Rachel is a stunt driver , and she escaping from a building .

D(t) models Rachel's remaining  distance ( in meters) a s  function of times t ( in seconds)

D(t)=-38 t+220

We have to find the speed of Rachel's

We know that speed is a absolute value of velocity

We are finding velocity

[tex]v=\frac{ds}{dt}[/tex]

[tex]v=\frac{d(-38t+220)}{dt}[/tex]

[tex]v=-38 m/s[/tex]

Speed=38 m/s

Hence, speed of Rachel's=38 m/s

Answer:

72.25 in^2

Step-by-step explanation:

Formula

Area = s^2 where s is the length of a side.

Given

s = 8.5 in

Solution

Area = s^2

Area = 8.5^2 = 8.5 * 8.5

Area = 72.25 in^2