The figure is not drawn to scale. Tank Y measuring 54 cm by 46 cm by 20 cm contained 29.97 ℓ of water. Tank Z measuring 45 cm by 30 cm by 34 cm contained 27 ℓ of water. Ian poured some water from Tank Y into Tank Z without spilling and the water level of Tank Z rose to 33 cm. What was the height of water level left in Tank Y?
1 ℓ = 1000 cm³
27 ℓ = 27000 cm³
29.97 ℓ = 29.97 x 1000 = 29970 cm³

Height of water in Tank Z at first
= 27000 ÷ 45 ÷ 30
= 20 cm

Increase in the height of water in Tank Z
= 33 - 20
= 13 cm

Volume of water poured into Tank Z
= 45 x 30 x 13
= 17550 cm³ 

Volume of water left in Tank Y
= 29970 - 17550
= 12420 cm³ 

Height of water left in Tank Y
= 12420 ÷ 54 ÷ 46
= 5 cm

Answer(s): 5 cm