The figure is not drawn to scale. Tank C measuring 50 cm by 43 cm by 25 cm contained 21.28 ℓ of water. Tank D measuring 40 cm by 34 cm by 36 cm contained 34 ℓ of water. Lee poured some water from Tank C into Tank D without spilling and the water level of Tank D rose to 28 cm. What was the height of water level left in Tank C?
1 ℓ = 1000 cm³
34 ℓ = 34000 cm³
21.28 ℓ = 21.28 x 1000 = 21280 cm³

Height of water in Tank D at first
= 34000 ÷ 40 ÷ 34
= 25 cm

Increase in the height of water in Tank D
= 28 - 25
= 3 cm

Volume of water poured into Tank D
= 40 x 34 x 3
= 4080 cm³ 

Volume of water left in Tank C
= 21280 - 4080
= 17200 cm³ 

Height of water left in Tank C
= 17200 ÷ 50 ÷ 43
= 8 cm

Answer(s): 8 cm