A car drives downhill with the speed of 90 m/h. On a level road, the same car goes 72 m/h, and uphill it goes "only" 60 m/h.

It takes this car 5 hours to go from town **A** to town **B**. The return trip only takes 4 hours.

Find the distance between the two towns.

(In reply to

Answer by K Sengupta)

During The onward journey, let the respective distance (in miles)

traveled uphill, level and downhill be P, Q and R.

Then it follows that, during the return journey, the respective distance traveled uphill, level and downhill are R, Q and P.

Accordingly, by conditions of the problem:

P/60 + Q/72 + R/90 = 5

P/90 + Q/72 + R/60 = 4

Adding, we obtain:

(P+Q+R)/36 = 9, giving:

P+Q+R = 324

Consequently, the distance between the two towns is 324 miles.