The figure is not drawn to scale. D and E are two containers. The base area of D is 24 cm² while the base area of E is 45 cm². Container D and E contained some water and the height of the water level in Container D was 57 cm as shown. Dan then poured some water from Container D into Container E. After that, the height of the water level in both tanks became 27 cm. What was the height of the water level in Container E at first?
Change in the water level of Container D
= 57 - 27
= 30 cm

Volume of water poured in the Container E
= 24 x 30
= 720 cm³ 

Height increase in Container E
= 720 ÷ 45
= 16 cm

Original height of the water in Container E
= 27 - 16
= 11 cm

Answer(s): 11 cm