A television camera is positioned 4000 ft from the base of a rocket launching pad. The angle of elevation of the camera has to change at the correct rate in order to keep the rocket in sight. Also, the mechanism for focusing the camera has to take into account the increasing distance from the camera to the rising rocket. Let's assume the rocket rises vertically and its speed is 800 ft/s when it has risen 3000 ft. (Round your answers to three decimal places.)
(a) How fast is the distance from the television camera to the rocket changing at that moment?
ft/s
(b) If the television camera is always kept aimed at the rocket, how fast is the camera's angle of elevation changing at that same moment?
rad/s
Answers
============================================
Explanation for part (a)
t = time in secondsx = horizontal distance from the camera to the launch pady = vertical distance from the launch pad to the rocket's locationz = distance from camera to the rocket at time tAll distances mentioned are in feet.
We'll have a right triangle which allows us to apply the pythagorean theorem. Refer to the diagram below.
a^2+b^2 = c^2
x^2+y^2 = z^2
Apply the derivative to both sides with respect to t. We'll use implicit differentiation and the chain rule.
[tex]x^2+y^2 = z^2\\\\\frac{d}{dt}[x^2+y^2] = \frac{d}{dt}[z^2]\\\\\frac{d}{dt}[x^2]+\frac{d}{dt}[y^2] = \frac{d}{dt}[z^2]\\\\2x*\frac{dx}{dt}+2y*\frac{dy}{dt}=2z*\frac{dz}{dt}\\\\x*\frac{dx}{dt}+y*\frac{dy}{dt}=z*\frac{dz}{dt}\\\\[/tex]
Now we'll plug in (x,y,z) = (4000,3000,5000). The x and y values are given. The z value is found by use of the pythagorean theorem. Ie, you solve 4000^2+3000^2 = z^2 to get z = 5000. Or you could note that this is a scaled copy of the 3-4-5 right triangle.
We know that dx/dt = 0 because the horizontal distance, the x distance, is not changing. The rocket is only changing in the y direction. Or you could say that the horizontal speed is zero.
The vertical speed is dy/dt = 800 ft/s and it's when y = 3000. It's likely that dy/dt isn't the same value through the rocket's journey; however, all we care about is the instant when y = 3000.
Let's plug all that in and isolate dz/dt
[tex]4000*0+3000*800=5000*\frac{dz}{dt}\\\\2,400,000=5000*\frac{dz}{dt}\\\\\frac{dz}{dt} = \frac{2,400,000}{5000}\\\\\frac{dz}{dt} = 480\\\\[/tex]
At the exact instant that the rocket is 3000 ft in the air, the distance between the camera and the rocket is changing by an instantaneous speed of 480 ft/s.
-----------------------------------------------------------------------
Explanation for part (b)
Again, refer to the diagram below.
We have theta (symbol [tex]\theta[/tex]) as the angle of elevation. As the rocket's height increases, so does the angle theta.
We can tie together the opposite side y with the adjacent side x with the tangent function of this angle.
[tex]\tan(\text{angle}) = \frac{\text{opposite}}{\text{adjacent}}\\\\\tan(\theta) = \frac{y}{x}[/tex]
Like before, we'll apply implicit differentiation. This time we'll use the quotient rule as well.
[tex]\tan(\theta) = \frac{y}{x}\\\\\frac{d}{dt}[\tan(\theta)] = \frac{d}{dt}\left[\frac{y}{x}\right]\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{\frac{dy}{dt}*x - y*\frac{dx}{dt}}{x^2}\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{800*4000 - 3000*0}{4000^2}\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{3,200,000}{16,000,000}\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{32}{160}\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{1}{5}\\\\[/tex]
Let's take a brief detour. We'll return to this later. Recall earlier that [tex]\tan(\theta) = \frac{y}{x}\\\\[/tex]
If we plug in y = 3000 and x = 4000, then we end up with [tex]\tan(\theta) = \frac{3}{4}\\\\[/tex] which becomes [tex]\tan^2(\theta) = \frac{9}{16}[/tex]
Apply this trig identity
[tex]\sec^2(\theta) = 1 + \tan^2(\theta)[/tex]
and you should end up with [tex]\sec^2(\theta) = 1+\frac{9}{16} = \frac{25}{16}[/tex]
So we can now return to the equation we want to solve
[tex]\sec^2(\theta)*\frac{d\theta}{dt} = \frac{1}{5}\\\\\frac{25}{16}*\frac{d\theta}{dt} = \frac{1}{5}\\\\\frac{d\theta}{dt} = \frac{1}{5}*\frac{16}{25}\\\\\frac{d\theta}{dt} = \frac{16}{125}\\\\\frac{d\theta}{dt} = 0.128\\\\[/tex]
This means that at the instant the rocket is 3000 ft in the air, the angle of elevation theta is increasing by 0.128 radians per second.
This is approximately 7.334 degrees per second.
The distance from the television camera to the rocket is changing at 480 ft/s while the camera's angle of elevation is changing at 0.128 rad/s
Let x represent the distance from the camera to the rocket and let h represent the height of the rocket.
a)
[tex]x^2=h^2+4000^2\\\\2x\frac{dx}{dt}=2h\frac{dh}{dt} \\\\x\frac{dx}{dt}=h\frac{dh}{dt} \\\\At \ h=3000\ ft, \frac{dh}{dt}=800\ ft/s;\\x^2=3000^{2} +4000^2\\x=5000\\\\\\x\frac{dx}{dt}=h\frac{dh}{dt} \\\\5000\frac{dx}{dt}=3000*800\\\\\frac{dx}{dt}=480\ ft/s[/tex]
b)
[tex]tan(\theta)=\frac{h}{4000} \\\\h=4000tan(\theta)\\\\\frac{dh}{dt}=4000sec^2(\theta)\frac{d\theta}{dt} \\\\\\At\ h=3000\ ft;\\\\tan\theta = \frac{3000}{4000}=\frac{3}{4} \\\\sec^2(\theta)=1+tan^2(\theta)=1+(\frac{3}{4})^2=\frac{25}{16} \\\\\\\frac{dh}{dt}=4000sec^2(\theta)\frac{d\theta}{dt}\\\\800=4000*\frac{25}{16}* \frac{d\theta}{dt}\\\\\frac{d\theta}{dt}=0.128\ rad/s[/tex]
Hence, The distance from the television camera to the rocket is changing at 480 ft/s while the camera's angle of elevation is changing at 0.128 rad/s
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Related Questions
At a sale this week, a desk is being sold for $312. This is a 35% discount from the original price.
What is the original price?
Answers
Answer:
$480
Step-by-step explanation:
Let original price be x
{Original price - discount amount = sale price}
So, x - (x * 35/100) = 312
x - 35x/100 = 312
100x - 35x / 100 = 312
65x/100 = 312
65x = 31200
x = 31200/65
x = $480
So I think the original price of desk was $480
The original price of the desk is $480.
What is discount?A discount is the reduction of either the monetary amount or a percentage of the normal selling price of a product or service.
Given that, a desk is being sold for $312.
Let the original price of the desk be x.
Here, x-35% of x =312
x- 35/100 ×x=312
x-0.35x=312
0.65x=312
x=312/0.65
x=480
Therefore, the original price of the desk is $480.
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14feet 23feet round each measurement to the nearest ten
Answers
20ft
I hope that’s correct ☺️
14 feet and 23
Step-by-step explanation:
It’s already rounded to the nearest tenth
find b for (b-1)/4=(7b+2)/12
Answers
Answer:
-1.25
Step-by-step explanation:
you first have to cross multiply
12(b-1)=4(7b+2)
12b-12=28b+8
group the like terms
12b-28b=8+12
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I hope it helps
Step-by-step explanation:
Answer is in the picture..
hope it helps
What is the domain of the function Y = In
-X+3
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O x32
O X<3
O
X> 3
ASAP
Answers
Answer:
i think 1/58 is correct
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Y= 3x-1
2x+6=y substitution method
Answers
Answer: (7, 20)
Concept:
There are three general ways to solve systems of equations:
EliminationSubstitutionGraphingSince the question has specific requirements, we are going to use substitution to solve the equations.
Solve:
Given equations
y = 3x - 1
2x + 6 = y
Substitute the y value since both equations has isolated [y]
2x + 6 = 3x - 1
Add 1 on both sides
2x + 6 + 1 = 3x - 1 + 1
2x + 7 = 3x
Subtract 2x on both sides
2x + 7 - 2x = 3x - 2x
[tex]\boxed{x=7}[/tex]
Find the value of y
y = 3x - 1
y = 3(7) - 1
y = 21 - 1
[tex]\boxed{y=20}[/tex]
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The height of a triangle is 4 yards greater than the base. The area of the triangle is 70 square yards. Find the length of the base and the height of the triangle.
Answers
9514 1404 393
Answer:
base: 10 yardsheight: 14 yardsStep-by-step explanation:
Let b represent the length of the base. Then (b+4) is the height and the area of the triangle is ...
A = 1/2bh
70 = 1/2(b)(b+4)
b² +4b -140 = 0 . . . . . multiply by 2, put in standard form
(b +14)(b -10) = 0 . . . . factor
b = 10 . . . . the positive solution
The base of the triangle is 10 yards; the height is 14 yards.
Sierra used the following steps to copy angle ABC:
1. Draw a ray with the endpoint D.
2. Place the compass on point B. Swing an arc that intersects rays BA and BC that creates point E on BA and Fon BC.
3. Keeping the compass at the same width, place it on point D, and swing an arc that creates point G on the ray.
4. Open the compass to the distance between points A and E.
5. Keeping the compass at the same width, place it on point G and swing an arc that intersects the arc created from point D.
6. Label the intersection of the arcs created from point D with point H, and draw a ray from point D through point H.
In which step did the error occur? Explain. (1 point)
Step 2. She did not set the proper compass length.
O Step 2. She drew an arc Instead of a circle.
Step 3. She placed the compass at an incorrect point.
Step 4. She measured the incorrect length.
Answers
The process of copying an angle through construction involve ensuring
that the distance between the two rays forming the angle is the same or
equal in the original and copy of the angle at a given equal distance from
the vertex of both angles
The step where the error occur is step 4. She measured the incorrect length
The reason for the above selection is as follows:
The steps to copy an angle are as follows;
Draw the initial line, l, (the working line) of the copy of the angle as a ray with an endpoint, DIn the given angle ∠ABC, with the compass placed at point B, construct an arc that intersect the two sides of the given line (BA at point E, and BC at point F) by opening the compass to a radius, rPlace the compass at the point D on the line l and with the radius r from above, draw an arc (D, r) that intersects the line l at the point GPlace the compass at point E on line AB, and construct an arc passing through point F, therefore having radial length EFPlace the compass at point G and construct an arc with radial length EF that intersects the arc (D, r) at point H and draw a ray from the point D passing through point H to complete the constructionA critical step in the copying process involves the finding the distance
between the initial line and the terminal line EF at a given distance DG =
AE from the angle vertex
The step where the error occur is in step 4. by opening the compass
between points A and E which are points on the same line and placing the
compass at point G on line l to draw an arc intersecting the arc created
from point D at H, thereby making the radial distance between the two lines
forming the angle, in the copied angle at a distance E from the vertex,
equal to AE rather than EF
Therefore, the error occurred in step 4. She measured the incorrect length
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Solve this inequality: 14 <-7x
Answers
Answer:
x > -2
Step-by-step explanation:
14 <-7x
or, 14/-7=-7x/-7
or, -2 < x
A single die is rolled twice. The 36 equally-likely outcomes are shown to the right. Find the probability of getting two numbers whose sum is 10 .
Answers
Answer:
The probability of getting two numbers whose sum is 10 is 25%.
Step-by-step explanation:
Given that a single die is rolled twice, and there are 36 equally-likely outcomes, to find the probability of getting two numbers whose sum is 10 the following calculation must be performed:
1 = +9
2 = +8
3 = +7
4 = +6
5 = +5
6 = +4
7 = +3
8 = +2
9 = +1
9/36 = 0.25
Therefore, the probability of getting two numbers whose sum is 10 is 25%.
Evaluate the expression 2x-xy if x= -1/2 and y=8
Answers
Answer:
3
Step-by-step explanation:
2x-xy
2(x)-(x)(y)
2(-1/2)-(-1/2)(8)
-1 - (-4)
-1 + 4
3
Answer:
3
Step-by-step explanation:
2x-xy
Let x = -1/2 and y = 8
2(-1/2) - (-1/2)(8)
Multiply
-1 - (-4)
Subtracting a negative is like adding
-1+4
Add
3
What is the length of the hypothenuse of the triangle?
Answers
Answer:
26ft
Step-by-step explanation:
10^2 +24^2 =AB^2
AB=26
Answer: 26 ft
Step-by-step explanation:
a^2+b^2=c^2
10^2+24^2 = c^2
100+576=c^2
Sqrt 676 = c
C = 26
QUESTION 2
A board is 86 cm. in lenght and must be cut so that one piece is 20 cm. longer than the other piece
Find the lenght of each piece.
A26 cm and 60 cm
b. 33 cm and 53 cm
C 30 cm and 56 cm
d. 70 cm and 16 cm
Answers
One piece will be length x and the other piece will be 20 cm longer, so it will be x + 20 cm long.
Added together the length of these two boards will equal 86 cm. So you can write an equation:
x + (x + 20) = 86
Remove the parentheses and add the two x's together to get:
2x + 20 = 86
Subtract 20 from both sides:
2x = 66
Divide both sides by 2 and you have:
x = 33
The short piece is 33 cm and the other piece is 20 cm longer or 33 + 20 = 53 cm.
Round 254 212 610 to the nearest million
Answers
Answer:
254,000,00
I hope this helps
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Answers
Answer:
Hello,
Answer A
Step-by-step explanation:
if x=0 then sin(2*0)=sin(0)=0
if x= π/4 then sin(π/2)=1
if x= π/2 then sin(π)=0
The equation of the sinusoid will be y=Sin(2x)
What is an equation?It is defined as the relation between two variables, for a sinusoidal wave the equation will be in the form of Sin or Cos.
if x=0 then sin(2*0)=sin(0)=0
if x= π/4 then sin(π/2)=1
if x= π/2 then sin(π)=0
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The perimeter of a square is 14 cm. Find the area
Answers
Step-by-step explanation:
A = 12.25cm2
P perimeter 14cm
Answer:
A=12.25cm²
P=14
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Answer:
8.5
Step-by-step explanation:
Answer:
5/2
Step-by-step explanation:
Since MR=MR and XM=MY and angle XMR = angle RMY,
then triangle XMR is congruent to triangle RMY by SAS postulate
Therefore, XR has to be equal to RY.
Making 6x+2=17
subtracting both sides by 2 gives you 6x=15
then dividing both sides by 6 gives you x=15/6
simplifying this fraction gives you x=5/2
Hope this helps.
please help !!!!
i would really appreciate it
Answers
Answer: A
Step-by-step explanation: x=-2, y=3, z=-3
Answer:
A. -2, 3, -3
Step-by-step explanation:
x = 7 - 2y + z
y = 21 + 6x + 2z = 21 + 6×(7 - 2y + z) + 2z =
= 21 + 42 - 12y + 6z + 2z = 63 - 12y + 8z
13y = 63 + 8z
y = (63 + 8z)/13
2x + 2y - 3z = 11
2×(7 - 2y + z) + 2×(63 + 8z)/13 - 3z = 11
2×(7 - 2×(63 + 8z)/13 + z) + 2×(63 + 8z)/13 - 3z = 11
14 - 4×(63 + 8z)/13 + 2z + 2×(63 + 8z)/13 - 3z = 11
-2×(63 + 8z)/13 - z = -3
-2×(63 + 8z) - 13z = -39
-126 - 16z - 13z = -39
-29z = 87
z = -3
y = (63 + 8×-3)/13 = (63 - 24)/13 = 39/13 = 3
x = 7 - 2×3 + -3 = 7 - 6 - 3 = -2
a game is played using one die. if the die is rolled and shows a 2, the player wins $45. If the die shows any number other than 2, the player wins nothing.
If there is a charge of $9 to play the game what is the games expected value?
Answers
Answer:
The game's expected value is of -$1.5.
Step-by-step explanation:
Expected value:
Probability of each outcome multiplied by the outcome.
One out of 6 sides is 2:
1/6 probability of the player earning 45 - 9 = $36.
5/6 probability of the player losing $9. So
[tex]E = 36\frac{1}{6} - 9\frac{5}{6} = \frac{36 - 45}{6} = -\frac{9}{6} = -1.5[/tex]
The game's expected value is of -$1.5.
simplify the following expression
6a^4c+8ac^2-4a^4c-15-10ac^2
Answers
Answer:
2a^4c-2ac^2-15
Step-by-step explanation:
Sorry, I not sure if this is right or not cause I don't know if the exponent for -4a^4c is that or -4a^4c-15, but I'm just going to go with -4a^4c. However aside from that you just combine like terms.
Answer:
[tex]2a^4c-2ac^2-15[/tex]
Step-by-step explanation:
[tex]6a^4c+8ac^2-4a^4c-15-10ac^2[/tex]
We need to organize this expression into groups of like terms, so we can combine them easier. There are 2 groups of like terms,
[tex]6a^4c-4a^4c[/tex] and [tex]8ac^2-10ac^2[/tex]
[tex]6a^4c-4a^4c+8ac^2-10ac^2-15[/tex]
Add similar elements:
[tex]2a^4c+8ac^2-10ac^2-15[/tex]
Add, [tex]8ac^2-10ac^2=-2ac^2[/tex]
[tex]=2a^4c-2ac^2-15[/tex]
OAmalOHopeO
Which of the following is not a rational number?
What are all possible integer solutions for b & p in the equation?
Answers
Answer:
4
Step-by-step explanation:
7+sqrt(7) is an irrational number
Answer:
p = 8 when b = 16 and p = -8 when
b = -16
Step-by-step explanation:
x² + bx + 64 = x² + 2px + p²
Cancel x² on both sides,
bx + 64 = 2px + p²
Now, by comparing both sides, you'll get the following equations,
1. b = 2p
2. p² = 64
From equation (2),
p = ±√64
= 8 or -8
Substitute p = 8 and p = -8 into equation (1),
b = 2(8) and b = 2(-8)
b = 2(8) and b = 2(-8) = 16 = -16
Therefore, p = 8 when b = 16 and p = -8 when
b = -16
Find the equation of the line: with a slope of -1/2 through (4,5)
Answers
Answer:
y=-1/2x+3
Step-by-step explanation:
y=mx+c
5=-1/2*4+c
5=-2+c
c=5-2
c=3
y=-1/2x+3
Which table represents a linear function?
Answers
Answer:
the the 3rd one Is the one
Suppose taxi fares from Logan Airport to downtown Boston is known to be normally distributed and a sample of seven taxi fares produces a mean fare of $21.51 and a 95% confidence interval of [$20.52, $22.48]. Which of the following statements is a valid interpretation of the confidence interval?
a. we are 95% confident that a randomly selected taxi fare will be between $2051 and $2421.
b. 95% of all taxi fares are between $2051 and $2421.
c. We are 95% confident that the average tau fare between Logan Airport and downtown Boston will fall between $2051 and $2421.
d. The mean amount of a taxi fare is $22.31, 95% of the time.
Answers
Answer:
c. We are 95% confident that the average taxi fare between Logan Airport and downtown Boston will fall between $20.51 and $24.21.
Step-by-step explanation:
x% confidence interval:
A confidence interval is built from a sample, has bounds a and b, and has a confidence level of x%. It means that we are x% confident that the population mean is between a and b.
95% confidence interval of [$20.52, $22.48].
We can be 95% sure that the true mean amount of taxis fares in downtown Boston is in this interval, and thus, the correct answer is given by option C.
pls help! I need the answer quickly! thank you!
Answers
The perimeter of a triangle is the summation of the three sides of the triangle. Base on the assumed values, the length of side BD is 2.
For [tex]\triangle ACD[/tex], the sides are: AC, AD and CD
So, the perimeter is:
[tex]P_{\triangle ACD} = AC + AD + CD[/tex]
For [tex]\triangle ABD[/tex], the sides are: AB, AD and BD
So, the perimeter is:
[tex]P_{\triangle ABD} = AB + AD + BD[/tex]
The difference in the perimeters is:
[tex]P_{\triangle ACD} - P_{\triangle ABD} =1 + \sqrt 3[/tex]
So, we have:
[tex](AC + AD + CD) - ( AB + AD + BD) =1 + \sqrt 3[/tex]
Open brackets
[tex]AC + AD + CD - AB - AD - BD =1 + \sqrt 3[/tex]
Evaluate like terms
[tex]AC + CD - AB - BD =1 + \sqrt 3[/tex]
Make BD the subject
[tex]BD = AC + CD - AB - (1 + \sqrt 3)[/tex]
The solution cannot be completed because the side lengths of [tex]\triangle ACD[/tex] and [tex]\triangle ABD[/tex] are not given; so, I will assume the following values.
[tex]AC =2; CD = 1; AB = \sqrt 3[/tex]
[tex]BD = AC + CD - AB - (1 + \sqrt 3)[/tex] becomes
[tex]BD = 2 + 1 + \sqrt 3 - (1 + \sqrt 3)[/tex]
Open bracket
[tex]BD = 2 + 1 + \sqrt 3 - 1 - \sqrt 3[/tex]
Evaluate like terms
[tex]BD = 2[/tex]
Base on the assumed values, the length of side BD is 2.
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(4m-n-3). 12n13
8m 20
Answers
Answer:
24n^7/m^16
Step-by-step explanation:
Just simplify and rewrite what ever you get simplify again 2 times and now make the calculation as you see every big number is a whole number and is a pair.
An average school bus holds 45 people. Sketch a graph showing the relationship between the number of students who need
bus transportation and the number of buses required. Be sure to label the axes. Homework Help
Answers
Graphs are used to show relationships between related entities. See attachment for the graph that shows the relationship between the number of students and the number of buses.
Given that:
[tex]People = 45\\[/tex]
[tex]Bus = 1[/tex]
The given parameters can be represented as:
[tex](x_1,y_1) = (45,1)[/tex]
Where:
[tex]x \to[/tex] people
[tex]y \to[/tex] bus
When there is nobody (i.e. 0 people), then the number of bus will also be 0. So, we have:
[tex](x_2,y_2) =(0,0)[/tex]
To sketch the graph that represents the given relationship, we simply plot points (0,0) and (45,1) and connect both points
See attachment for the graph
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Review the example argument and reasoning below. Identify the form (inductive or deductive) of reasoning and the type (example, analogy, causal correlation, syllogism, sign, or causal generalization) of reasoning Raul uses to justify his argument. Then, apply the three tests of argumentative reasoning (quantity, quality, & opposition) to test this argument.
Raul believes that if someone’s eyes shift to the left when they are responding to a question it is evidence that they are lying. While interviewing Michael, Raul notices Michael's eyes shifting to the left frequently when answering questions. Later, Raul tells a coworker that Michael was not hired because Raul believed Michael had lied about his previous experience during the interview.
Answers
Answer:
inductive - . Inductive reasoning makes broad generalizations from specific observations.
casual correlation
quality ( i think)
Step-by-step explanation:
Answer:
A
Step-by-step explanation:
i just did it
If you wanted to make a game where you pay $5 if you can't guess a random dogs weight within 16lbs what payout should you offer you make the game zero-expected value
Answers
Answer:
Following are the solution to the given question:
Step-by-step explanation:
The population std. dev of the dog weight=8
[tex]\sigma=8\\\\P(\text{guess with in 16 lbs}) = P(|X-\mu|\leq 16)\\\\=P(-2 \leq Z \leq 2) = 0.9544\\\\[/tex]
Calculating the payout w s.t:
[tex]E[netpay]=0=(-5) \times 0.9544+w\times (1-0.9544)\\\\ w =(5 \times \frac{0.9544}{1-0.9544}) =\$ 104.65[/tex]
therefore, we assume that the weight of the dog is a normal distribution with std. deviation that is 8.
What are the solutions?
Answers
It's the third option.
Completing the square yields
x ² + 9x + 7 = 0
(x ² + 9x + 81/4) + 7 = 81/4
(x + 9/2)² + 7 = 81/4
Now solving for x gives
(x + 9/2)² = 53/4
x + 9/2 = ± √(53/4) = ± √53/2
x = (-9 ± √53)/2
40 percent of the teachers at a meeting are male.
Of the male teachers at the meeting, 20 percent
teach mathematics. Which of the following
could be the possible number of teachers at the
meeting?
(A) 60
(B) 64
(C) 72
(D) 75
(E) 80
Answers
Answer:
D. 75
Step-by-step explanation:
To find the possible number of teachers at the meeting, find which answer choice creates a whole number answer when calculating the 40% of teachers that are male and the 20% of them that teach math.
This number is answer choice D, 75.
40% of 75 is 30.
Of those 30 teachers, 20% of 30 is 6.
So, since each quantity is a whole number, this could be the possible number of teachers at the meeting.
The correct answer is D. 75
