Explanation:
I am not sure about the meaning of the last question, but we will get there.
so, his own speed is 8 mph.
d = the given distance (half-trip) in miles.
time = distance / speed
t = time to travel downstream in hours
t + 2 = d/(8 - 3)
t = d/(8 + 3)
we use the second equation in the first
d/(8 + 3) + 2 = d/(8 - 3)
d/11 + 2 = d/5
5d/11 + 10 = d
5d + 110 = 11d
6d = 110
3d = 55
d = 55/3 = 18.33333333...
he will row 2×d (round trip) = 36.6666666... miles =
= 36 2/3 miles
t = d/(8 + 3) = 18.3333333... / 11 =
= 1.666666666... =
= 1 2/3 hours =
= 1 hour 60×2/3 minutes =
= 1 hour 120/3 = 1 hour 40 minutes
it will take him 1 hour 40 minutes to row downstream.
he will row 36 2/3 miles in total.