The rate of the water's current is 2 mph
Step-by-step explanation
Let r represents the rate of water's currrent. (In miles per hour)
Downstream
Distance = 10 miles Rate = 3+r
Using d = rt,
t = d/r
Upstream
Distance = 2 miles Rate = 3- r
Times are the same
Hence, equate the two ts
Cross-multiply
10(3-r) = 2(3+r)
Open the parenthesis.
30 - 10r = 6 + 2r
collect like term
30 - 6 = 2r + 10r
24 = 12r
Divide both-side by 12
2 = r
r = 2
Therefore, the rate of the water's current is 2 mph