The figure is not drawn to scale. Tank J measuring 54 cm by 42 cm by 15 cm contained 38.68 ℓ of water. Tank K measuring 40 cm by 25 cm by 36 cm contained 15 ℓ of water. Oscar poured some water from Tank J into Tank K without spilling and the water level of Tank K rose to 31 cm. What was the height of water level left in Tank J?
1 ℓ = 1000 cm³
15 ℓ = 15000 cm³
38.68 ℓ = 38.68 x 1000 = 38680 cm³

Height of water in Tank K at first
= 15000 ÷ 40 ÷ 25
= 15 cm

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

Volume of water poured into Tank K
= 40 x 25 x 16
= 16000 cm³ 

Volume of water left in Tank J
= 38680 - 16000
= 22680 cm³ 

Height of water left in Tank J
= 22680 ÷ 54 ÷ 42
= 10 cm

Answer(s): 10 cm