Explanation:
volume of a cylinder is
ground area × height = pi×r²×h
r = 4
what we need to calculate is how high the water stands with one "serving" of 2m³.
that height is then added every minute (with the additional 2m³ during that minute).
so,
2 = pi×4²×h = pi×16×h
2/16 = 1/8 = pi×h
h = (1/8) / pi = 1/(8pi) = 0.039788736... m
that is rounded about 0.04 m or 4 cm.
therefore, the water rises by 0.04 m or 4 cm per minute
0.04m/min