Question
The speed of a stream is 6 mph. If a boat travels 52 miles downstream in the same time that it takes to travel 26 miles upstream, what is the speed of the boat in still water?
Answers
Reiny
let the speed of the boat in still water be x mph
using Distance = rate x time or Time = distance/rate
upstream:
time = 26/(x-6)
downstream:
time = 52/(x+6)
26/(x-6) = 52/(x+6)
cross-multiply
52x - 312 = 26x + 156
26x = 468
x = 18
boat's speed is 18 mph
using Distance = rate x time or Time = distance/rate
upstream:
time = 26/(x-6)
downstream:
time = 52/(x+6)
26/(x-6) = 52/(x+6)
cross-multiply
52x - 312 = 26x + 156
26x = 468
x = 18
boat's speed is 18 mph