A boat's crew rowed 10.5 miles downstream, with the current, in 1.5 hours. The return trip upstream, against the current, covered the same distance, but took 3.5 hours. Find the crew's rowing rate in still water, and the rate of the current.

Answer 1

(Vb+Vc)1.5 = 10.5
Eq1: Vb + Vc = 7

(Vb-Vc)3.5 = 10.5
Eq2: Vb - Vc = 3
Add Eq1 and Eq2:

Vb + Vc = 7
Vb - Vc = 3

2Vb = 10
Vb = 5 mi/h

5 + Vc = 7
Vc = 2 mi/h.