Four pipes can fill a reservoir in 15, 20, 30 and 60 hours respectively. The first one was opened at 6 AM, second at 7 AM, third at 8 AM and the fourth at 9 AM. When will the reservoir be filled ?
A. 11 AM
B. 12 Noon
C. 1 PM
D. 1:30 PM
Answer:C
Four pipes can fill a reservoir in 15, 20, 30 and 60 hours respectively. The first one was opened at 6 AM, second at 7 AM, third at 8 AM and the fourth at 9 AM. When will the reservoir be filled ?
A. 11 AM B. 12 Noon C. 1 PM D. 1:30 PM