Multiple choice general knowledge math & puzzles

Faucet A fills a tank in 3 hours, and faucet B drains the tank in 9 hours. What fraction of the tank will be filled, if both the faucets are kept running for 1½ hours, and the tank is originally empty?

  1. 1/4

  2. 1/3

  3. 1/2

  4. 2/3

  5. 3/4

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

Faucet A fills at 1/3 tank per hour, faucet B drains at 1/9 tank per hour. Net fill rate = 1/3 - 1/9 = 2/9 tank per hour. In 1.5 hours: 2/9 × 3/2 = 1/3 tank. Option B is correct.