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.

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




her walking speed.= 2mph