The figure is not drawn to scale. Tank W measuring 50 cm by 46 cm by 25 cm contained 11.86 ℓ of water. Tank X measuring 40 cm by 31 cm by 37 cm contained 31 ℓ of water. Owen poured some water from Tank W into Tank X without spilling and the water level of Tank X rose to 29 cm. What was the height of water level left in Tank W?
1 ℓ = 1000 cm³
31 ℓ = 31000 cm³
11.86 ℓ = 11.86 x 1000 = 11860 cm³

Height of water in Tank X at first
= 31000 ÷ 40 ÷ 31
= 25 cm

Increase in the height of water in Tank X
= 29 - 25
= 4 cm

Volume of water poured into Tank X
= 40 x 31 x 4
= 4960 cm³ 

Volume of water left in Tank W
= 11860 - 4960
= 6900 cm³ 

Height of water left in Tank W
= 6900 ÷ 50 ÷ 46
= 3 cm

Answer(s): 3 cm