Question

A tap can empty a tank in one hour. A second
tap can empty it in 30 minutes. If both the taps
operate simultaneously, how much time is
needed to empty the tank ?
(a) 20 min.
(b) 30 min.
(c) 40 min.
(d) 45 min.​

Answer 1

Step-by-step explanation:

1 hr = 60 min.

Rate of emptying the tank by the 2 taps

$\frac{1}{60} \: and \: \frac{1}{30}$

Rate of emptying the tank when both operate simultaneously =

Rate of emptying the tank when both operate simultaneously ==

$\frac{1}{60} + \frac{1}{30}$

$= \frac{1 + 2}{60}$

$\frac{3}{60}$

$\frac{1}{20}$

∴ Time taken by the two taps together to empty the tank = 20 minutes.