Question

A tap can empty a tank in an hour and half and another tap can empty the same tank in half an hour. If both the taps operate simultaneously, then how much time (in minutes) is required to empty the tank?

A  17.5

B  20

C  22.5

D  25

Give the answer with explaination
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Answer 1

Answer:

Step-by-step explanation:

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]45 minutes

[B]20 minutes

[C]40 minutes

[D]30 minutes

20 minutes

1 hour = 60 minutes

Rate of emptying the tank by the two taps are \frac{1}{60} and \frac{1}{30} of the tank per minute respectively.

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}

of the tank per minute.

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

Hence option [B] is the right answer.