5 identical 9-cm cubes are placed in an empty rectangular tank of length 71 cm and width 28 cm. The tank is then filled with water from a tap flowing at a rate of 10 litres per minute. It takes 9 minutes to fill up ³₄ of the tank. What is the height of the tank? Correct your answer to 1 decimal place.
Volume of 1 cube
= 9 x 9 x 9
= 729 cm³ 

Volume of 5 cubes
= 5 x 729
= 3645 cm³ 

1 ℓ = 1000 mℓ
10 ℓ = 10000 mℓ

Volume of water in the tank
= 9 x 10000
= 90000 mℓ

Volume of ³₄ of the tank
= 90000 + 3645
= 93645 mℓ

Volume of the tank
= 93645 ÷ ³₄
= 93645 x ⁴₃
= 124860 mℓ

Base area
= 71 x 28
= 1988 cm² 

Height of the tank
= 124860 ÷ 1988
≈ 62.8 cm

Answer(s): 62.8 cm