The opening of a tunnel that travels through a mountainside can be modeled by [tex]y = - \frac {2}{15} (x - 15)(x + 15)[/tex], where x and y are measured in feet. The x-axis represents the ground.
​a. Find the width of the tunnel at ground level.
b. How tall is the tunnel?

Answers

Answer 1

Answer:

(a) 30 feet

(b) 30 feet.

Step-by-step explanation:

Given that the opening of a tunnel that travels through a mountainside can be modeled by

[tex]y=\frac{-2}{15} (x-15)(x+15)[/tex], where x and y are measured in feet.

[tex]\Rightarrow y=\frac{-2}{15}(x^2-15^2}[/tex]

[tex]\Rightarrow y=\frac{-2}{15}{x^2-225}\cdots(i)[/tex]

(a) At the ground level, [tex]y=0[/tex]

So, the width of the tunnel at ground level is distance between the extreme point of the tunnel on the grount.

For, [tex]y=0[/tex], the extreme points of the tunnel.

[tex]0=\frac{-2}{15} (x-15)(x+15)[/tex]

[tex]\Rightarrow (x-15)(x+15) =0[/tex]

[tex]\Rightarrow x= 15, -15[/tex]

So, the extreme points of the tunnel are, [tex]x_1=15[/tex] and [tex]x_2=-15[/tex].

Hence, the width of the tunnel at the ground level

[tex]= | x_1 - x_2 |[/tex]

[tex]=|15-(-15)|[/tex]

[tex]=30[/tex] feet.

(b) The maximum height of the tunnel can be determiment by determining the maxima of the given function.

First determining the value of x for which the slope of the graph is zero.

[tex]\frac{dy}{dx}=0[/tex]

From equation (i),

-2x=0

[tex]\Rightarrow x=0[/tex]

And  [tex]\frac{d^2y}{dx^2}= -2[/tex]

which is always negative, so at x=0 the value of y is maximum.

Again, put x=0 in equation (i), we have

[tex]y=\frac{-2}{15}{0^2-225}[/tex]

[tex]\Rightarrow y=30[/tex] feet.

Hence, the tunnel is 30 feet tall.


Related Questions

is 800 cm greater than 8 cm

Answers

Answer:

100

Step-by-step explanation:

Write sec 325° in terms of the secant of'a positive acute angle.

Answers

Answer:

sec35°

Step-by-step explanation:

sec325° = sec(360 - 325)° = sec35°

The secant of a positive acute angle of sec 325° = sec 35° = 1.22077

What are Trigonometric Ratios?

Trigonometry values are all about the study of standard angles for a given triangle with respect to trigonometric ratios.The six trigonometric ratios are sine (sin), cosine (cos), tangent (tan), cotangent (cot), cosecant (cosec), and secant (sec).

Given data ,

The trigonometric ratio is = sec 325°

Now , to express the ratio in terms of a positive acute angle , we take the four quadrants of the graph and express the angle in the first quadrant.

And , 325° lies on the 4th Quadrant , where all cosines and secants are positive.

Therefore , sec 325° = sec ( 360° - 35° )

                                  = sec ( 35° )

                                  =1.22077

Hence , the secant of a positive acute angle of sec 325° = sec 35° = 1.22077

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A rectangular room is covered in 5 12 square feet of carpet. If the length of the room is 16 feet,
what is the width of the room?

Answers

Answer:

long

Step-by-step explanation:

14ft

what is the answer a, b, c, or d

Answers

Answer: Choice B

(-2, 5)

==================================================

Explanation:

The original system is

[tex]\begin{cases}-4x+3y = 23\\ x-y = -7\end{cases}[/tex]

Multiply both sides of the second equation by 3. Doing so leads to this updated system of equations

[tex]\begin{cases}-4x+3y = 23\\ 3x-3y = -21\end{cases}[/tex]

Now add straight down

The x terms add to -4x+3x = -1x = -x

The y terms add to 3y+(-3y) = 0y = 0

The terms on the right hand sides add to 23+(-21) = 2

We end up with the equation  -x = 2 which solves to x = -2

Now use this to find y. You can pick any equation with x,y in it

----------------

-4x+3y = 23

-4(-2)+3y = 23

8+3y = 23

3y = 23-8

3y = 15

y = 15/3

y = 5

Or

x-y = -7

-2-y = -7

-y = -7+2

y = -5

y = 5

Either way, we get the same y value.

So that's why the solution is (x,y) = (-2, 5)

A bowl contains 5 blue marbles, 2 yellow marbles, 10 black marbles, and 3 white marbles. Without
looking, what is the probability that Fiona pulls out a marble that is not white?

Answers

Answer:

85%

Step-by-step explanation:

The probability that Fiona pulls out a marble that is not white from a  bowl which contains 5 blue marbles, 2 yellow marbles, 10 black marbles, and 3 white marbles is 17/20.

What is the probability of an event?

Probability of an event is the ratio of number of favorable outcome to the total number of outcome of that event.

As the probability of an event can not be more than the number 1. Thus the probability of failure of a event is equal to the difference of the 1 to the success of the event.

A bowl contains 5 blue marbles, 2 yellow marbles, 10 black marbles, and 3 white marbles.  The total number of marbles in the bowl is,

[tex]n=5+2+10+3\\n=20[/tex]

The number of white balls in the bowl is 3. Thus, the probability that Fiona pulls out a marble that is white, is,

[tex]P=\dfrac{3}{20}[/tex]

The probability that Fiona pulls out a marble that is not white is,

[tex]P^{-1}=1-\dfrac{3}{20}\\P^{-1}=\dfrac{20-3}{20}\\P^{-1}=\dfrac{17}{20}[/tex]

Thus, the probability that Fiona pulls out a marble that is not white from a  bowl which contains 5 blue marbles, 2 yellow marbles, 10 black marbles, and 3 white marbles is 17/20.

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Jenny wants to buy a new dress for her first school dance she barrows $25.63 from her sister to help pay for the dress then Jenny earns $16.33 helping her dad organize his home office if she gives all the earnings to her sister Jenny will still owe her sister $

Answers

Answer:

Jenny will owe her sister $9.30

Step-by-step explanation:

Subtract the money she earned from her dad from what she borrowed from her sister. $25.63-$16.33=$9.30 :)

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28x+36y=2520 Write this in slope intercept form or graph!!

Answers

Answer:

y= -7/9 x+70

Step-by-step explanation:

28x+36y=2520

36y=-28x+2520

y= -7/9 x+70

write in standard form 9 times 100

Answers

Answer:

900

Step-by-step explanation:

100 x 9 = 900

cuase 1 x 9 = 9 and add two zero 900

Answer:

9*10²

Step-by-step explanation:

10*10=100

9*100=900

What is the value of x in the equation x*3 = 27 512 ?

Answers

Answer:
9,170.67

Explanation:
27,512 divided by 3 = 9,170.67
X=3

New equation:
9,170.67 * 3 = 27,512
Sorry if this is wrong

A billboard on level ground is supported by a brace as shown in the accompanying diagram the measure of angle is 15° greater than twice the measure of angle b determine the measure of angle a in the measure of angle b

Answers

Answer:

has a right angle to hold the billboard upright. Since a triangle is 180, and there' s a right angle, then when you add angle A and angle B together, they should add up to 90.

Step-by-step explanation:

A  = 2B + 15

A + B = 2B+15 + B = 90

3B + 15 = 90

3B = 75, so B = 25 degrees

90 - B = A, so A = 65 degrees

Which difference is closest to 12?
A. 89−1112
B. 67−19
C. 1516−38
D. 35−611

Answers

Answer:

b

The rest are at least 500 numbers away from 12

Step-by-step explanation:

g + 10 = 3g

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Answers

The sum of g and 10 equals the product of 3 and h

Consider the equation −3+(−9.25)+m=0 .

Answers

Let's solve your equation step-by-step.

−3−9.25+m=0

Step 1: Simplify both sides of the equation.

−3−9.25+m=0

−3+−9.25+m=0

(m)+(−3+−9.25)=0(Combine Like Terms)

m+−12.25=0

m−12.25=0

Step 2: Add 12.25 to both sides.

m−12.25+12.25=0+12.25

m=12.25

Answer:

m=12.25

2\3n = -12 what value of n makes this equation true

Answers

Answer:

-0.055555555555556

Step-by-step explanation:

need help pease its due at 11;59pm today explian

Answers

Answer:

65

Step-by-step explanation:

you add all the numbers inside.

80+35= 115

You have to make sure it equals to 180 to find angle 1.

Therefore, 180-115=65.

The distance between the Sun and each planet in our solar system varies because the planets travel in elliptical (oval) orbits around the Sun rather than completely circular ones.

Here is a table of the average distance and the variation in the distance for the five innermost planets in our solar system:

Average Distance and Variation
Planet Name Average Distance Variation
Mercury 36.0 million miles 7.39 million miles
Venus 67.2 million miles 0.43 million miles
Earth 93.0 million miles 1.55 million miles
Mars 142 million miles 13.2 million miles
Jupiter 484 million miles 23.2 million miles


"Average distance" means the mean distance that planet is from the sun over the course of its orbit, and "variation" means how far it varies from that mean. For example, if a planet had an average distance of 5 miles and a variation of one mile, it would have distances between 4 and 6 miles at different times.

a) Write and solve an inequality to represent the range of distances that can occur between the Sun and one of the planets from the table (your choice). Show your steps/process.

b) Why is this best represented as an inequality rather than an equation? Explain in at least 3 sentences.

Answers

Answer:

Hope this helps

Step-by-step explanation:

They describe how (1) planets move in elliptical orbits with the Sun as a focus, (2) a planet covers the same area of space in the same amount of time no matter where it is in its orbit, and (3) a planet's orbital period is proportional to the size of its orbit (its semi-major axis)

Answer:

because

Step-by-step explanation:

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Answers

Answer:

B

Step-by-step explanation:

1/5 is larger than 1/10

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Given f(x) = -5(2x-7 )- 19, what is the
value of f(-2)?

Answers

Answer:

X=1.8

Step-by-step explanation:

f(X)=-2

-5(2x-7)-19=-2

-10x+35-19+2=0

-10x=-18

X=-18÷(-10)

X=1.8

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Answer:

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Step-by-step explanation:

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Step-by-step explanation:

They are equal hope this helps

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Answers

Answer:

1 true

2 false

3 true

4 false

5 true

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Step-by-step explanation:

A jar contains 50 coins, all either 2 cents or 5 cents. The total value of the coins is $1.87.
How many 2 cents coins are there?

Answers

Answer:

there would be 21 cents

Answer:

they would be 21 cents coins

HOPE IT WILL HELP U!

A math test had 26 questions. The questions were either true/false or multiple choice. The true/false questions were worth 2 points each and the multiple choice were worth 5 points each. If the test is worth 100 points, how many of each type of question are included on the test?

Answers

Answer:

True/ false type 10 questions

Multiple choice type 16 questions  

Step-by-step explanation:

Using the given formation we can make equations to solve for the number of questions of either type is to be included

let the no of true/false be =x

let the number of multiple choice to be included be = y

x + y=26  .............(1)

now making the equation of points

2x + 5y = 100 .........(2)

substitute y = 26-x from first equation in the second equation

2x + 5(26 - x ) = 100

2x - 5x + 130 = 100

3x=30

x=10

y =26-10=16

HELP ME PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :3
I have to do what the image below says but I don't know how to write it:,)

Answers

Answer:

To write an equation in slope-intercept form, given a graph of that equation, pick two points on the line and use them to find the slope. This is the value of m in the equation. Next, find the coordinates of the y-intercept--this should be of the form (0, b). The y- coordinate is the value of b in the equation.

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Answers

Answer: 24695374195

Step-by-step explanation: did you really need this?

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Answers

Step-by-step explanation:

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Answers

Answer:

B

Step-by-step explanation:

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Answers

Answer:

one group has 12. one has 16. 12 + 16 = 28. 16 is 4 more than 12

Graph the line through 2,3 that is Parallel to the line with the equation 3x-y=2

Answers

Answer:

y=3x-3

Step-by-step explanation:

first we turn in the stander from to y incept form

then you plug in the x and y, for time here, i am not goona put the steps more

msg me if you need steps

Write the exponential equation for the given situation. A tennis tournament starts with 128 participants. Each round, half of the participants gets eliminated from the tournament

Answers

Answer:

y= 128(1-.5)^t

Step-by-step explanation:

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