The figure is not drawn to scale. Tank S measuring 50 cm by 41 cm by 21 cm contained 24.45 ℓ of water. Tank T measuring 40 cm by 25 cm by 36 cm contained 21 ℓ of water. Billy poured some water from Tank S into Tank T without spilling and the water level of Tank T rose to 27 cm. What was the height of water level left in Tank S?
1 ℓ = 1000 cm³
21 ℓ = 21000 cm³
24.45 ℓ = 24.45 x 1000 = 24450 cm³

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

Increase in the height of water in Tank T
= 27 - 21
= 6 cm

Volume of water poured into Tank T
= 40 x 25 x 6
= 6000 cm³ 

Volume of water left in Tank S
= 24450 - 6000
= 18450 cm³ 

Height of water left in Tank S
= 18450 ÷ 50 ÷ 41
= 9 cm

Answer(s): 9 cm