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rjkz [21]
2 years ago
9

The driver of a car travelling downhill on a road applies the brakes. The speed s

Mathematics
1 answer:
Pepsi [2]2 years ago
3 0

The maximum speed reached is 89 km/h after 1.5 seconds.

<h3>Speed</h3>

Given the speed s of the car in km/h, t seconds after the brakes were applied.

s(t) = -4t² + 12t + 80

a) The brakes were applied at t = 0, hence:

  • s(0) = -4(0)² + 12(0) + 80 = 80 km/h

b) At s = 88:

88 = -4t² + 12t + 80

t = 2 seconds and t = 1 second

c) The maximum speed is at s'(t) = 0

s'(t) = -8 t + 12 = 0

8t = 12

t = 1.5 seconds

s(1.5) = -4(1.5)² + 12(1.5) + 80 = 89 km/h

The maximum speed reached is 89 km/h after 1.5 seconds.

Find out more on speed at: brainly.com/question/4931057

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Krystal can wax a floor in 16 minutes. Perry helped her and it took 5.76 minutes. How long would it take perry to do it alone?
finlep [7]
<span>Krystal's rate = 1 floor in 16 min. = 1/16 floors per min.

Working together their rate = 1 floor in 5.76 min. = 1/5.76 floors per min.

We need to determine Perry's rate, so we need to equate their combined rate with the sum of the individual rates.

Let Perry's time = x

In equation form, we can write:
1/16 + 1/x = 1/5.76
Solve for x:

(x+16)/16x = 1/5.76 -> 5.76(x+16) = 16x -> 10.24x = 92.16 -> x = 9

So, Perry would take 9 mins. to do the floor alone.

I hope this helped!
Please Rate & Thank!
Please mark as Brainliest!

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8 0
3 years ago
The sum of two numbers is 15. four times the smaller number is 60 less than twice the larger number. what is the larger number?
kirza4 [7]
X = smaller number, y = larger number
x + y = 15.....x = 15 - y
4x = 2y - 60

4(15 - y) = 2y - 60
60 - 4y = 2y - 60
60 + 60 = 2y + 4y
120 = 6y
120/6 = y
20 = y <==== larger number is 20

x + y = 15
x + 20 = 15
x = 15 - 20
x = - 5
4 0
3 years ago
26. If x:3 = 12:x, calculate the positive value of x.​
nydimaria [60]

Answer:

Answer ::+-6

Step-by-step explanation:

x:3=12:x

or, x/3 = 12/x

Doing cross multiplication,

x^2=36

Putting sqare root on both sides,

x= sqrt. 36

x= +- 6

Therefore x=+-6.

6 0
3 years ago
Read 2 more answers
Show work how you know it’s a function or not a function for each problem. PLEASE SOMEONE HELP ME OUT
Fudgin [204]

Answer: Function, not a function, Function, not a function

Step-by-step explanation:

For it to be a function, each value of x has to map onto one value of y.

  1. This is a function.
  2. Not a function since x=-1 has more than one y value.
  3. This is a function
  4. Not a function since x=-6 has more than one y value.
7 0
1 year ago
F(x) =x2-17x+60 how to find the zeros of the function​
sergiy2304 [10]

Answer:

x = 1&16

Step-by-step explanation:

f(x) = 0 then

0 =x^2 - 17x + 16

(x-1)(x-16) =0

x -1 =0 or x-16=0

x =1 & x = 16

3 0
3 years ago
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