The figure is not drawn to scale. W and X are two containers. The base area of W is 28 cm² while the base area of X is 40 cm². Container W and X contained some water and the height of the water level in Container W was 63 cm as shown. Dan then poured some water from Container W into Container X. After that, the height of the water level in both tanks became 30 cm. What was the height of the water level in Container X at first?
Change in the water level of Container W
= 63 - 30
= 33 cm

Volume of water poured in the Container X
= 28 x 33
= 924 cm³ 

Height increase in Container X
= 924 ÷ 40
= 23.1 cm

Original height of the water in Container X
= 30 - 23.1
= 6.9 cm

Answer(s): 6.9 cm