Multiple choice general knowledge math & puzzles

Every day in his business a merchant had to weigh amounts from 1 kg to 121 Kgs, to the nearest kg. What are the minimum numbers of weight required?

  1. 2

  2. 4

  3. 5

  4. 7

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

Using weights of 1, 3, 9, 27, and 81 kg allows measuring any integer weight from 1 to 121 kg by placing weights on either side of the balance. This works because these are powers of 3, and 1+3+9+27+81=121, covering the full range through balanced ternary representation.