SOLUTION: if a girl ran for 3 miles, then decreased her speed by 1 and ran for 4 miles and ran for a total of 96 minutes. what were her 2 speeds/

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Question 754100: if a girl ran for 3 miles, then decreased her speed by 1 and ran for 4 miles and ran for a total of 96 minutes. what were her 2 speeds/
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
if a girl ran for 3 miles, then decreased her speed by 1 and ran for 4 miles and ran for a total of 96 minutes. what were her 2 speeds.
***
let x=speed during 3-mile run
x-1=speed during 4-mile run
travel time=distance/speed
..
3%2Fx%2B4%2F%28x-1%29=%2896%2F60%29%28hrs%29
3%2Fx%2B4%2F%28x-1%29=%288%2F5%29%28hrs%29
LCD:5x(x-1)
15x-15%2B20x=8x%5E2-8x
8x^2-43x+15=0
(x-5)(8x-3)=0
x=5
or
x=3/8(reject, not reasonable)
her 2 speeds are 5 mph and 4 mph