Quantitative Aptitude Ques 1868
Question: There are 7 pipes attached with a tank out of which some are inlets and some are outlets. Every inlet can fill the tank in 10 h and every outlet can empty the tank in 15 h. When all the pipes are opened simultaneously, the tank is filled up in $ 2\frac{8}{11}h. $ Find the numbers of inlets and outlets.
Options:
A) 5, 2
B) 6, 1
C) 4, 3
D) 3, 4
E) None of these
Show Answer
Answer:
Correct Answer: A
Solution:
- Let number of outlets be x.
$ \therefore $ Number of inlets $ =(7-x) $ Time taken to fill the tank when all the pipes are opened $ =\frac{30}{11}h $ Part of tank filled in 1 h when all the pipes are opened $ =\frac{11}{30}h $ According to the question, $ \frac{7-x}{10}-\frac{x}{15}=\frac{11}{30} $
$ \Rightarrow $ $ \frac{3(7-x)-2x}{30}=\frac{11}{30} $
$ \Rightarrow $ $ 21-3x-2x=11 $
$ \Rightarrow $ $ 5x=10 $
$ \therefore $ $ x=2 $ Hence, number of outlets $ =2 $ and number of inlets $ =7-2=5 $
BETA
