Question

One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 minutes, then the slower pipe alone will be able to fill the tank in :

• A. 80 min
• B. 144 min
• C. 108 min
• D. 180 min

Answer 1

Answer:

B. 144 min

if slower pipe takes x minutes to fill the tank faster pipe takes x/3 minutes to fill the tank Part of the tank filled by slower pipe in 1 minute = 1/x Part of the tank filled by faster pipe in 1 minute = 3/x 1/x + 3/x = 1/36 4/x = 1/36 x = 4 × 36 = 144 minutes