3 identical 9-cm cubes are placed in an empty rectangular tank of length 74 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 ¹₂ 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 3 cubes
= 3 x 729
= 2187 cm³ 

1 ℓ = 1000 mℓ
9 ℓ = 9000 mℓ

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

Volume of ¹₂ of the tank
= 99000 + 2187
= 101187 mℓ

Volume of the tank
= 101187 ÷ ¹₂
= 101187 x ²₁
= 202374 mℓ

Base area
= 74 x 23
= 1702 cm² 

Height of the tank
= 202374 ÷ 1702
≈ 118.9 cm

Answer(s): 118.9 cm