The figure is not drawn to scale. Tank M measuring 55 cm by 46 cm by 16 cm contained 32.71 ℓ of water. Tank N measuring 40 cm by 25 cm by 35 cm contained 16 ℓ of water. Warren poured some water from Tank M into Tank N without spilling and the water level of Tank N rose to 31 cm. What was the height of water level left in Tank M?
1 ℓ = 1000 cm³
16 ℓ = 16000 cm³
32.71 ℓ = 32.71 x 1000 = 32710 cm³

Height of water in Tank N at first
= 16000 ÷ 40 ÷ 25
= 16 cm

Increase in the height of water in Tank N
= 31 - 16
= 15 cm

Volume of water poured into Tank N
= 40 x 25 x 15
= 15000 cm³ 

Volume of water left in Tank M
= 32710 - 15000
= 17710 cm³ 

Height of water left in Tank M
= 17710 ÷ 55 ÷ 46
= 7 cm

Answer(s): 7 cm