A hiking club set out at 12 noon The members hiked along a l

A hiking club set out at 12 noon. The members hiked along a level road at a rate of 4 mph; up a mountain trail at 3 mph;immediately back down the mountain trail at 6 mph,and back home along the level road again at 4 mph. They got back at 6pm. How far did the club hike?

Solution

It seems you have missed some conditions,so you should check this question
first.
Assume the level road isL miles and the mountain trail is M miles,then
we have
2 L/4 + M/3+ M/6 = 6,
Cancel the denominators:
or 3L + 2M + M = 36....(*)
This is an equation of two variables, so there are infinite many solutions.
Suppose L = M, then (*) becomes
6L = 36, so L = M = 6 miles.