jim began a 92​-mile bicycle trip to build up stamina for a triathlon competition.​ Unfortunately, his bicycle chain​ broke, so he finished the trip walking. The whole trip took 4 hours. If Jim walks at a rate of 3 miles per hour and rides at 35 miles per​ hour, find the amount of time he spent on the bicycle.

3 answers

Spent X hrs. on bike.
Spent 4-X hrs. walking.

35x + 3(4-x) = 92.
X = ?.
4-x = ?.
let b equal distance on bicycle

(b / 35) + [(92 - b) / 5] = 4 ... solve for b

time on bicycle = b / 35
since time = distance/speed, if he rode for x miles, then
x/35 + (92-x)/3 = 4
x = 87.5 miles
now you can find the time he spent riding.