Question

The highway mileage m in miles per gallon for a compact car is approximated by m(s) = -0.025s^2 + 2.45s - 30, where s is the speed in miles per hour. What is the maximum mileage for this compact car to the nearest tenth of a mile per gallon? __________ mi/gal.

Answer 1

also to the nearest whole number as well. I'm so confused. help!

Answer 2

I this question in your parabola or quadratic equation chapter

Answer 3

yes

Answer 4

both

Answer 5

have you bee using graphing calculators

Answer 6

use you graphing calc and plug in for y= your equation

Answer 7

dont have one.

Answer 8

hmmm...oh, you just need to max value for s, right?

Answer 9

yes

Answer 10

remember, the graph will point downwards since the leading term has a -.....remember that?

Answer 11

so you need the max s value which at the vertex...top of the parabola when sketched out....lkooks like the path when you throw a ball up and it comes back down...got the picture?

Answer 12

so you can find the x value of the vertex by using -a/2b....where a is the coeficient of the leading term and b is the coefficient of the second, or linear, term.

Answer 13

ok make since so far.

Answer 14

so you'll have -(-0.025)/2(2.45)......have a regular calculator?

Answer 15

that's backwards.....-b/2a = -2.45/2(-0.025)= 49 so plug in the 49 for s and evaluate....

Answer 16

are you still there??