The figure is not drawn to scale. Tank M measuring 48 cm by 47 cm by 25 cm contained 30.96 ℓ of water. Tank N measuring 40 cm by 35 cm by 34 cm contained 35 ℓ of water. Valen 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
35 ℓ = 35000 cm³
30.96 ℓ = 30.96 x 1000 = 30960 cm³

Height of water in Tank N at first
= 35000 ÷ 40 ÷ 35
= 25 cm

Increase in the height of water in Tank N
= 31 - 25
= 6 cm

Volume of water poured into Tank N
= 40 x 35 x 6
= 8400 cm³ 

Volume of water left in Tank M
= 30960 - 8400
= 22560 cm³ 

Height of water left in Tank M
= 22560 ÷ 48 ÷ 47
= 10 cm

Answer(s): 10 cm