4 identical 9-cm cubes are placed in an empty rectangular tank of length 90 cm and width 27 cm. The tank is then filled with water from a tap flowing at a rate of 7 litres per minute. It takes 12 minutes to fill up ¹₃ 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 4 cubes
= 4 x 729
= 2916 cm³ 

1 ℓ = 1000 mℓ
7 ℓ = 7000 mℓ

Volume of water in the tank
= 12 x 7000
= 84000 mℓ

Volume of ¹₃ of the tank
= 84000 + 2916
= 86916 mℓ

Volume of the tank
= 86916 ÷ ¹₃
= 86916 x ³₁
= 260748 mℓ

Base area
= 90 x 27
= 2430 cm² 

Height of the tank
= 260748 ÷ 2430
≈ 107.3 cm

Answer(s): 107.3 cm