If one tank has an 80 x 80cm cross section; the other has a 60 x 60cm cross section. if I pour 100 litres of oil into the larger tank, by how much will the level of the oil in the smaller tank rise?

Answer 1

assuming the tanks are connected at their bases, the oil will equalize when the depth is the same in both tanks.

80*80*h1 = 60*60*h2
h2/h1 = 64/36 = 16/9

9 cm in the larger tank equals 6400*9cm^3 = 57.6 liters
16 cm in the smaller tank holds 3600*16cm^3 = 57.6 liters

scale those depths by 100/115.2 to get the final depths.