The figure is not drawn to scale. Z and A are two containers. The base area of Z is 15 cm² while the base area of A is 50 cm². Container Z and A contained some water and the height of the water level in Container Z was 57 cm as shown. Dan then poured some water from Container Z into Container A. After that, the height of the water level in both tanks became 29 cm. What was the height of the water level in Container A at first?
Change in the water level of Container Z
= 57 - 29
= 28 cm

Volume of water poured in the Container A
= 15 x 28
= 420 cm³ 

Height increase in Container A
= 420 ÷ 50
= 8.4 cm

Original height of the water in Container A
= 29 - 8.4
= 20.6 cm

Answer(s): 20.6 cm