We can split the prism into 2 parts
The "top" part has a volume of
1 m x 2 m x .6m = 1.2 m^3
The "bottom" part has a volume of
[ 1m x 2m x .8m] / 2 = .8m^3
And the volume of water that drains in 30 minutes =
1m x 2m x .2m = .4m^3
So....the total time for the pool to drain =
[1.2 m^3 + .8m^3] / .4m^3 x 30 min =
[ 2 m^3 / .4m^3 ] x 30 min =
5 x 30 min = 150 min = 2.5 hrs
= Infinity
