The area of the hole is 3^2 in^2 = 9 in^2.
There are 144 in^2 in 1 ft^2, so that area is 9/144 = 0.0625 ft^2
so water flows out at 9/144 * v cu ft/sec, = v / 64 cu ft/sec
So over the first minute (60 sec), the amount of water that flows out
= ∫ [for 0 < t < 60] v / 64 dt