Quantitative Aptitude Ques 779
Question: A pipe of diameter d can drain a certain water tank in 40 min. The time taken by a pipe of diameter 2d for doing the same job in
Options:
A) 5 min
B) 10 min
C) 20 min
D) 80 min
Show Answer
Answer:
Correct Answer: B
Solution:
- Given, $ t _1=40, $ $ d _1=d, $ $ d _2=2d $ Time $ \propto \frac{1}{Crosssectionareaofpipe} $
$ \Rightarrow $ $ t _1\propto \frac{1}{\frac{\pi }{4}d_1^{2}} $ and $ t _2\propto \frac{1}{\frac{\pi }{4}d_2^{2}} $
$ \Rightarrow $ $ \frac{t _2}{t _1}={{( \frac{d _1}{d _2} )}^{2}} $
$ \therefore $ $ t _2=40{{( \frac{d}{2d} )}^{2}}=10\min $
BETA
