Question 548626
Let the boat speed be x mph
against current (x-4)mph
distance traveled before breakdown = 2(x-4)
upstream
time =2 hours

return
time =
2(x-4)/4

2(x-4)/4 + 2 = 5.5

1/2(x-4)=3.5

x-4 = 7
x=11 mph