The figure is not drawn to scale. Tank X measuring 50 cm by 42 cm by 25 cm contained 21.22 ℓ of water. Tank Y measuring 40 cm by 29 cm by 34 cm contained 29 ℓ of water. Seth poured some water from Tank X into Tank Y without spilling and the water level of Tank Y rose to 27 cm. What was the height of water level left in Tank X?
1 ℓ = 1000 cm³
29 ℓ = 29000 cm³
21.22 ℓ = 21.22 x 1000 = 21220 cm³

Height of water in Tank Y at first
= 29000 ÷ 40 ÷ 29
= 25 cm

Increase in the height of water in Tank Y
= 27 - 25
= 2 cm

Volume of water poured into Tank Y
= 40 x 29 x 2
= 2320 cm³ 

Volume of water left in Tank X
= 21220 - 2320
= 18900 cm³ 

Height of water left in Tank X
= 18900 ÷ 50 ÷ 42
= 9 cm

Answer(s): 9 cm