28
A pipe of diameter d can drain a certain water tank in 40 minutes. The time taken by a pipe of diameter 2d for doing the same job in :
- A5 minutes
- B10 minutes
- C20 minutes
- D80 minutes
Answer not set
Log in or create a free account to reply and vote.
0
CCommunity
Time is inversely proportional to the square of diameter. So,
$ \frac{t1}{t2} = \frac{(d2)^2}{(d1)^2} $
$\frac{40}{t2} = \frac{(2d)^2}{(d)^2}$
Solve, t2 = $10$ mins
$ \frac{t1}{t2} = \frac{(d2)^2}{(d1)^2} $
$\frac{40}{t2} = \frac{(2d)^2}{(d)^2}$
Solve, t2 = $10$ mins
0
CCommunity
Its very simple question 10 minutes is the correct answer.
0
CCommunity
ans : 10 minutes