Quantitative Aptitude Ques 1927
Question: If two pipes function together, the tank will be filled in 12 h. One pipe fills the tank in 10 h faster than the other. How many hours does the faster pipe take to fill up the tank?
Options:
A) 20
B) 60
C) 15
D) 25
Show Answer
Answer:
Correct Answer: A
Solution:
- Let one pipe takes m h to fill the tank. Then, the other pipe takes $ (m-10)h. $ According to the question,
$ \therefore $ $ \frac{1}{m}+\frac{1}{(m-10)}=\frac{1}{12} $
$ \Rightarrow $ $ \frac{m-10+m}{m(m-10)}=\frac{1}{12} $
$ \Rightarrow $ $ 12(m-10+m)=m(m-10) $
$ \Rightarrow $ $ m^{2}-34m+120=0 $
$ \Rightarrow $ $ m^{2}-30m-4m+120=0 $
$ \Rightarrow $ $ (m-30)(m-4)=0 $
$ \therefore $ $ m=30 $ or 4
$ \therefore $ Faster pipe will take $ (30-10)h=20h $ to fill the tank.
BETA
