The figure is not drawn to scale. Tank W measuring 55 cm by 47 cm by 16 cm contained 30.51 ℓ of water. Tank X measuring 40 cm by 25 cm by 37 cm contained 16 ℓ of water. Fred poured some water from Tank W into Tank X without spilling and the water level of Tank X rose to 31 cm. What was the height of water level left in Tank W?
1 ℓ = 1000 cm³
16 ℓ = 16000 cm³
30.51 ℓ = 30.51 x 1000 = 30510 cm³

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

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

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

Volume of water left in Tank W
= 30510 - 15000
= 15510 cm³ 

Height of water left in Tank W
= 15510 ÷ 55 ÷ 47
= 6 cm

Answer(s): 6 cm