<PRE><B>Question 349630</B>
Hi,
*Note: d= r*t  t= d/r

.
time is the same up and down the river
{{{50mi/(35 -c) = 75mi/(35+c)}}}
.
Cross multiply to solve
75*(35 -c) = 50*(35+c)
.
divide both sides of the equation by 25
3(35-c) = 2*(35+c)
105 - 3c = 70 +2c
35 = 5c
c = 7(mi/hr)
.
Speed going down the river is 35(mi/hr) + 7(mi/hr)= 42(mi/hr)
.
check your answer
50/28 = 75/42</PRE>