Let's take Pump 1 and Pump 2

Rectangular prism shaped pool
Take length = l width = b depth = h

Volume of pool 1 = lbh

Pump 1 will take 1 hr to fill the water of volume \(lbh\)

Pool 2 has twice the length and twice the width and same depth

Volume of pool 2 = \((2*l)(2*b)(h)\) = \(4lbh\)

Pump 1 will take with it's speed to fill pool 2, 4 hours.

Now it is given that pump 2 fills twice the water than pump 1. So the speed will be half than the time taken by pump 2.

So Pump 2 will take 2 hours to fill Pool 2.


Answer B