SOLUTION: Melissa walks 3 miles to the house of a friend and returns home on a bike. She averages 4 miles per hour faster when cycling than when walking, and the total time for both trips is
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Question 1003712: Melissa walks 3 miles to the house of a friend and returns home on a bike. She averages 4 miles per hour faster when cycling than when walking, and the total time for both trips is two hours. Find her walking speed. Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! Melissa walks 3 miles to the house of a friend and returns home on a bike. She averages 4 miles per hour faster when cycling than when walking, and the total time for both trips is two hours. Find her walking speed.
Melissa walks 3 miles to the house of a friend and returns home on a bike.
let the speed be x
she takes 3/x hours to reach
She averages 4 miles per hour faster when cycling than when walking,
speed = (x+4)
time taken = 3/(x+4)
and the total time for both trips is two hours.
3/x + 3/(x+4) = 2
multiply the equation by x(x+4)
3(x+4)+3x = 2x(x+4)
3x+4+3x = 2x^2+8x
2x^2+2x-4=0
/2
x^2+x-2=0
x^2-2x+x-2=0
x(x-2)+1(x-2)=0
(x-2)(x+1)=0
x=2 OR -1
ignore negative
x=2
