A pool has two inlet pumps A and B. If pump A alone is open, it takes 12 hours to fill the pool with water. If pump B alone is open, it takes 18 hours to fill the pool with water. If the pool needs to be filled in 10 hours, what is the least amount of time (in hours) both pumps need to be open?

The least amount of time (in hours) both pumps need to be open is 3 hours.

Step-by-step explanation:

According to the Question,

Let the Capacity of the Pool is 36Litre.

If the pool needs to be filled in 10 hours the least amount of time (in hours) both pumps need to be open is 3 hours.

Note:- if 3 hour both pipe open so 3 x (5) = 15 ltr Pool is Filled.

Now For Remaining 7 hour Pipe A with Efficiency 3 ltr/hour is open alone to fill the pool Remaining 7 x 3 = 21 ltr . Total 21+15 = 36ltr .

the answer is b

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