SOLUTION: A bicycle trip of 90 miles would have taken an hour less if the average speed had been increased by 3 mi/h. Find the average speed of the bicycle.
Algebra ->
Customizable Word Problem Solvers
-> Travel
-> SOLUTION: A bicycle trip of 90 miles would have taken an hour less if the average speed had been increased by 3 mi/h. Find the average speed of the bicycle.
Log On
Question 519968: A bicycle trip of 90 miles would have taken an hour less if the average speed had been increased by 3 mi/h. Find the average speed of the bicycle. Answer by mananth(16949) (Show Source):
You can put this solution on YOUR website! let speed be x
t=d/r
time with original speed - time with increased speed = 1
90/x-90/(x+3)=1
LCD=x(x+3)
multiply by LCD
90(x+3)-90x=x(x+3)
90x+270-90x=x^2+3x
x^2+3x-270=0
x^2+18x-15x-270=0
x(x+18)-15(x+18)=0
(x+18)(x-15)=0
x=15 ignoring negative value
speed = 15 mph
m.ananth@hotmail.ca
