Multiple choice general knowledge math & puzzles

A fish wants to swim 25 km upstream. he swims 7 km in the day and floats back 5 km at night. how many days will it take for the fish to reach 25 km upstream?

  1. 10 days

  2. 12.5 days

  3. 9 days

  4. 7 days

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

The fish makes net progress of 7 - 5 = 2 km per full day (day swim + night float back). After 9 days, it reaches 18 km (9 × 2). On the 10th day, starting from 18 km, it swims 7 km to reach exactly 25 km and achieves its goal - it doesn't float back since it has arrived. This type of problem requires tracking the final day separately.