The figure is not drawn to scale. Tank D measuring 52 cm by 41 cm by 21 cm contained 31.32 ℓ of water. Tank E measuring 40 cm by 25 cm by 32 cm contained 21 ℓ of water. Will poured some water from Tank D into Tank E without spilling and the water level of Tank E rose to 31 cm. What was the height of water level left in Tank D?
1 ℓ = 1000 cm³
21 ℓ = 21000 cm³
31.32 ℓ = 31.32 x 1000 = 31320 cm³

Height of water in Tank E at first
= 21000 ÷ 40 ÷ 25
= 21 cm

Increase in the height of water in Tank E
= 31 - 21
= 10 cm

Volume of water poured into Tank E
= 40 x 25 x 10
= 10000 cm³ 

Volume of water left in Tank D
= 31320 - 10000
= 21320 cm³ 

Height of water left in Tank D
= 21320 ÷ 52 ÷ 41
= 10 cm

Answer(s): 10 cm