Answer the Following with Solutions:

Question

1. A boat row downstream a distance of 5 miles in 15 minutes, but it takes 20 minutes for the return trip. Find the rate of the boat in still water.
2. A boat row downstream a distance of 5 miles in 15 minutes, but it takes 20 minutes for the return trip. Find the rate of the current.

Answer 1

Rate x Time = Distance

Downstream rate x 0.25 hours = 5 miles, so downstream rate = 20 mph

Upstream rate x 0.33 hours = 5 miles, so upstream rate = 15 mph

Downstream rate = rowing rate (r) + current rate (c) and upstream rate = r - c, so

20 = r + c

15 =r - c

Solve simultaneous equations. r = 17.5 mph (rate in still water) and c = 2.5 mph (rate of the current)