Question

Three pipes can fill a tank in 15 hours, 12 hours and 10 hours, respectively. If all the three pipes are opened simultaneously for 3 hours, then what percentage of the tank will remain unfilled?

• A. 17%
• B. 50%
• C. 33%
• D. 25%

Answer 1

Answer:

D. 25%

Solution: Given: Three pipes can fill a tank in 15 hours, 12 hours and 10 hours, respectively. If all the three pipes are opened simultaneously for 3 hours Concept Used: Pipe and cistern Calculation: Three pipes can fill a tank in 15 hours, 12 hours and 10 hours, respectively To find the total capacity take lcm of three Lcm of 15,12 and 10 is 60 Total capacity = 60 unit which is 100% Efficiency of Pipe A = 60/15 = 4 Efficiency of Pipe B = 60/12 = 5 Efficiency of Pipe C = 60/10 = 6 As per the question, All three pipes were opened for 3 hours ⇒ (4 + 5 + 6) × 3 ⇒ 45 unit work done Remaining work ⇒ 60 - 45 = (15/60) × 100 = 25%