Multiple choice

Pipes A and B can empty a fully filled tank in 8 and 12 hours respectively. C is a filling pipe. These three pipes were opened at the same time and in one hour the sixth part of the tank became empty in one hour. In how much time can C fill the tank alone? पाइप A और B एक पूरी तरह से भरे हुए टैंक को क्रमशः 8 और 12 घंटे में खाली कर सकते हैं। C एक भरने वाला पाइप है। इन तीनों पाइपों को एक साथ खोल दिया गया और एक घंटे में टंकी का छठा हिस्सा एक घंटे में खाली हो गया। C अकेले टंकी को कितने समय में भर सकता है?

  1. 25 hours 25 घंटे

  2. 20 hours 20 घंटे

  3. 30 hours 30 घंटे

  4. 24 hours 24 घंटे

  5. 22 hours 22 घंटे
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A and B are emptying pipes with rates 1/8 and 1/12 per hour. C is a filling pipe with unknown rate r. Together: 1/8 + 1/12 - r = 1/6 (emptying rate per hour). Solving: (3+2)/24 - r = 1/6, so 5/24 - r = 4/24, giving r = 1/24 per hour. Therefore C alone fills the tank in 24 hours. Option A (25 hours) would result if the net effect was slightly less than 1/6. Option C (30 hours) would require r = 1/30.

Keep practicing — related questions