The figure is not drawn to scale. X and Y are two containers. The base area of X is 12 cm² while the base area of Y is 14 cm². Container X and Y contained some water and the height of the water level in Container X was 50 cm as shown. Dan then poured some water from Container X into Container Y. After that, the height of the water level in both tanks became 29 cm. What was the height of the water level in Container Y at first?
Change in the water level of Container X
= 50 - 29
= 21 cm

Volume of water poured in the Container Y
= 12 x 21
= 252 cm³ 

Height increase in Container Y
= 252 ÷ 14
= 18 cm

Original height of the water in Container Y
= 29 - 18
= 11 cm

Answer(s): 11 cm