9 identical 9-cm cubes are placed in an empty rectangular tank of length 88 cm and width 23 cm. The tank is then filled with water from a tap flowing at a rate of 9 litres per minute. It takes 11 minutes to fill up ³₅ 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 9 cubes
= 9 x 729
= 6561 cm³ 

1 ℓ = 1000 mℓ
9 ℓ = 9000 mℓ

Volume of water in the tank
= 11 x 9000
= 99000 mℓ

Volume of ³₅ of the tank
= 99000 + 6561
= 105561 mℓ

Volume of the tank
= 105561 ÷ ³₅
= 105561 x ⁵₃
= 175935 mℓ

Base area
= 88 x 23
= 2024 cm² 

Height of the tank
= 175935 ÷ 2024
≈ 86.9 cm

Answer(s): 86.9 cm