The figure is not drawn to scale. Tank C measuring 51 cm by 45 cm by 20 cm contained 26.76 ℓ of water. Tank D measuring 40 cm by 35 cm by 36 cm contained 28 ℓ of water. Rael poured some water from Tank C into Tank D without spilling and the water level of Tank D rose to 26 cm. What was the height of water level left in Tank C?
1 ℓ = 1000 cm³
28 ℓ = 28000 cm³
26.76 ℓ = 26.76 x 1000 = 26760 cm³

Height of water in Tank D at first
= 28000 ÷ 40 ÷ 35
= 20 cm

Increase in the height of water in Tank D
= 26 - 20
= 6 cm

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

Volume of water left in Tank C
= 26760 - 8400
= 18360 cm³ 

Height of water left in Tank C
= 18360 ÷ 51 ÷ 45
= 8 cm

Answer(s): 8 cm