Multiple choice general knowledge math & puzzles

A bicycle rider went a mile in three minutes with the wind, and returned in four minutes against the wind. How fast could he ride a mile if there was no wind?

  1. approx. 3 minutes 30 seconds

  2. approx. 3 minutes 29 seconds

  3. approx. 3 minutes 27 seconds

  4. approx. 3 minutes 26 seconds

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When riding with the wind, the rider's speed is the sum of their own speed and the wind speed. Against the wind, the wind speed subtracts from their speed. By adding the two speeds (20 mph and 15 mph), the wind speed cancels out, giving twice the rider's still-air speed of 17.5 mph. Converting back to time for 1 mile gives approximately 3 minutes 26 seconds.