SOLUTION: A cyclist travels a distance of 120km from Town A to Town B at an average speed of x km/h. If he increases his speed by 1km/h, he would save 30 minutes. Find x
Algebra ->
Customizable Word Problem Solvers
-> Travel
-> SOLUTION: A cyclist travels a distance of 120km from Town A to Town B at an average speed of x km/h. If he increases his speed by 1km/h, he would save 30 minutes. Find x
Log On
Question 839167: A cyclist travels a distance of 120km from Town A to Town B at an average speed of x km/h. If he increases his speed by 1km/h, he would save 30 minutes. Find x Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! A cyclist travels a distance of 120km from Town A to Town B at an average speed of x km/h. If he increases his speed by 1km/h, he would save 30 minutes. Find x
Original Time - time after speed increase = 1/2 hour
multiply the equation by 2x(x+1)
we get
2*120(x+1) -2*120*x = x(x+1)
240x+240 -240x=x^2+x
x^2+x-240=0
x^2+16x-15x-240=0
x(x+16)-15(x+16)=0
(x+16)(x-15)=0
x cannot be negative
so x=15
