The figure is not drawn to scale. S and T are two containers. The base area of S is 13 cm² while the base area of T is 25 cm². Container S and T contained some water and the height of the water level in Container S was 70 cm as shown. Dan then poured some water from Container S into Container T. After that, the height of the water level in both tanks became 30 cm. What was the height of the water level in Container T at first?
Change in the water level of Container S
= 70 - 30
= 40 cm

Volume of water poured in the Container T
= 13 x 40
= 520 cm³ 

Height increase in Container T
= 520 ÷ 25
= 20.8 cm

Original height of the water in Container T
= 30 - 20.8
= 9.2 cm

Answer(s): 9.2 cm