Henry Ernest Dudeney/Modern Puzzles/33 - A Rowing Puzzle

Modern Puzzles by Henry Ernest Dudeney: $33$

A Rowing Puzzle

A crew can row a certain course upstream in $8 \tfrac 4 7$ minutes,

and, if there were no stream, they could row it in $7$ minutes less than it takes them to drift down the stream.

How long would it take to row down with the stream?

Sources

• 1926: Henry Ernest Dudeney: Modern Puzzles ... (previous) ... (next): Arithmetical and Algebraical Problems: Locomotion and Speed Puzzles: $33$. -- A Rowing Puzzle
• 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Arithmetical and Algebraical Problems: Speed & Distance Puzzles: $61$. A Rowing Puzzle