Quantitative Aptitude Ques 1126

Question: Pipes P and Q can fill a tank in 10 and 12 h, respectively and C can empty it in 6 h. If all the three are opened at 7 am, at what time will one-fourth of the tank be filled? [SSS (CPO) 2011]

Options:

A) 10 am

B) 10 pm

C) 11 pm

D) 11 am

Show Answer

Answer:

Correct Answer: B

Solution:

  • Given, tank filled by $ P=10h, $ filled by $ Q=12h $ and emptied by $ C=6h $ Part of tank filled in $ 1h $ when all three pipes are opened $ =\frac{1}{10}+\frac{1}{12}-\frac{1}{6}=\frac{6+5-10}{60}=\frac{1}{60} $ Hence, the tank will be filled in $ 60h. $

$ \therefore $ One-fourth of the tank will be filled in $ =\frac{60}{4}=15h $ i.e. the tank will be filled at 10 pm.