SOLUTION: What is Amy's speed if she travels 450 miles at a certain speed. If the car had gone 15mph faster, the trip would have taken 1 hour less?

Question 298972: What is Amy's speed if she travels 450 miles at a certain speed. If the car had gone 15mph faster, the trip would have taken 1 hour less?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
let her speed be x
she traveled 450 miles
time taken by her = 450/x
if her speed was x-15 it would have taken 450 /x + 15
450/x - 450 / x+15 = 1
450(x+15)-450x / x(x+15)=1
450x +6750-450x =x^2 +15x
x^2+15x-6750=0
x^2+90x-75x-6750=0
x(x+90)-75(x+90)=0
(x-75)(x+90)=0
x=75 a positive value which is her speed

RELATED QUESTIONS
Amy travels 450 miles at a certain speed. If the car had gone 15mph faster, the trip... (answered by Paul)

Amy travels 450 miles at a certain speed. If the car had gone 15mph faster, the trip... (answered by venugopalramana)

I need help with this Amy travels 450 miles at certain speed. If the car had gone 15... (answered by ankor@dixie-net.com)

Imogene's car traveled 450 miles at certain speed. If car had gone 5 mph faster, the... (answered by ankor@dixie-net.com)

Sam's Subaru travels 280 miles at a certain speed. if the car had gone 5 mph faster, the (answered by oberobic)

amy travels 450 miles at a certain speed. If the car had gone 15 mph faster, the trip... (answered by richwmiller)

A car travels 380 miles averaging a certain speed. If the car had gone 5 mph faster the... (answered by Alan3354)

A car travels 910 miles at a certain speed. If the speed had been 5mph faster the trip... (answered by ankor@dixie-net.com)