K.3 Same depth of the water in the vessel

There is water to a depth of 10 cm in A.
When the water of A is put into B and it is the same depth of the water of A and B, what cm is the depth of the water?

Answer

6 cm

Solution

The volume of water is divided by the sum of the base area of A and B, then you can find the depth of water. 

The volume of water is 10 × 15 × 10 = 1500 cm³, the sum of the base area of A and B is 10 × 15 + 10 × 10 = 250 cm². 

The depth of water is 1500/250 = 6 (cm).