Question 638272
Let d = the distance travelled before breaking down.
For the outbound trip in the car, the travel time = d/40 [time = distance/speed]
For the return trip on the bike, the travel time = d/10 [same distance travelled]
The total time = 4 hr, so we can write
d/40 + d/10 = 4
Solve for d:
(40d + 10d)/400 = 4
50d = 1600
d = 32
So you travelled 32 miles before breaking down