Question

A tap can fill a drum in 60 minutes. After it was opened for 20 minutes, a hole is made at the bottom of the drum to drain the water. The drum is filled 120 minutes after the hole is made. In how many minutes can the hole empty the entire drum?

Answer 1

✨ Here is your answer
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Whole tank is divided into 3 equal sections A, B, & C = 1/3 . Section A has been filled with water in 20 minutes.

Then a hole is made & tap is opened. Water starts dripping through hole.

That is, dripping & filling go simultaneously. Now, if we assume water starts dripping from section B. ( as this assumption does not make any difference in the final time calculated)

In section B, in 20 minutes 4th, 5th & 6th parts are supposed to be filled, [Divided into 3 parts as (120÷2)/20 = 3 & given that after the hole is made time given is 120 min.] but because of dripping , 4th & 5th parts get emptied in 20 min & water is filled only in 6th part.

So, now we found that 4th & 5th parts are emptied in 20 minutes.

& 4th + 5th part = [2/3 of 1/3 of 1 full tank ] = 2/9

=> 2/9 part of the tank is emptied in 20 min

=> 1 entire part is filled in 20 ÷ 2/9

= 20 * 9/2 = 90 minutes . . . . . . . Ans
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✨ Mark it BRAINLIEST

Answer 2

Answer:

The tap can fill the drum in 60 minutes

So in the 20 minutes it has filled the 1/3rd of the tank

Since    1    -    60

              ?   -    20

                    -->1/3

So after 20 minutes,the tap and hole both worked together to fill the remaining 2/3rd of the tank.It takes 120 minutes(given).

       

Work done by Tap and Hole--->2/3    -     120(2 hrs)

                                                       1      -      ?

                                                             -->180 mins(3 hrs)

The tap takes 1 hr to fill the tank

Both tap and hole takes 3 hrs to fill the tank

Finally,the hole needs

        -->Product/difference hrs

            =(1*3)/2

            =1.5 hrs

            =90 minutes to empty the tank