Quantitative Aptitude Ques 2387
Question: Two pipes A and B can fill a cistern in $ 37\frac{1}{2}\min $ min and 45 min respectively. Both pipes are opened. The cistern will be filled just in half an hour, if the pipe B is turned off after
Options:
A) 15 min
B) 10 min
C) 5 min
D) 9 min
Show Answer
Answer:
Correct Answer: D
Solution:
- Pipe A fills the tank in $ \frac{75}{2}\min . $
$ \therefore $ Part of the tank filled by A in 30 min $ =\frac{2}{75}\times 30=\frac{4}{5} $ Remaining part $ =1-\frac{4}{5}=\frac{1}{5} $ Now, 1 part is filled by pipe B in 45 min.
$ \therefore $ $ \frac{1}{5} $ part is filled in $ 45\times \frac{1}{5}=9,\min $ Hence, the pipe B should be turned off after 9 min.
BETA
