Multiple choice

A pipe can fill a cistern in 9 hours. Due to a leak in its bottom, the cistern fills up in 10 hours. If the cistern is full, in how much time will it be emptied by the leak? एक पाइप एक टंकी को 9 घण्टे में भर सकती है इसके तली में रिसाव के कारण टंकी को भरने में 10 घण्टे लगते है यदि टंकी पूरी भरी है तो रिसाव के द्वारा कितने समय में खाली हो जायेगी?

  1. 70 hours/घंटे

  2. 80 hours/घंटे

  3. 90 hours/घंटे

  4. 100 hours/घंटे
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pipe's filling rate is 1/9 cistern per hour. With leak, effective rate is 1/10 per hour. The leak's rate alone is the difference: 1/9 - 1/10 = 1/90 (emptying). Thus, it takes 90 hours to empty a full cistern. Option A (70 hours) and B (80 hours) underestimate the leak time. Option D (100 hours) incorrectly treats the leak as faster.

Keep practicing — related questions