Question

Alicia can row 6 miles downstream in the same time it takes her to row 4 miles upstream. she rows downstream 5 miles/hour faster than she rows upstream. find alicia's rowing rate each way. round your answers to the nearest tenth, if necessary.

Answer 1

Let x be the speed she rows upstream.

Upstream

speed = distance / time

x = 4 / t.................................(1)
downstream
x + 5 = 6 / t...........................(2)
from  (1)
t = 4/x
Substituting in (2):-
x + 5 = 6 / (4/x)
x + 5 = 3x / 2
2x + 10 = 3x
x = 10 

ANSWER IS  rowing rate upstream is 10 mph and downstream its 15 mph.