7 identical 6-cm cubes are placed in an empty rectangular tank of length 73 cm and width 22 cm. The tank is then filled with water from a tap flowing at a rate of 7 litres per minute. It takes 11 minutes to fill up ⁴₅ of the tank. What is the height of the tank? Correct your answer to 1 decimal place.
Volume of 1 cube
= 6 x 6 x 6
= 216 cm³ 

Volume of 7 cubes
= 7 x 216
= 1512 cm³ 

1 ℓ = 1000 mℓ
7 ℓ = 7000 mℓ

Volume of water in the tank
= 11 x 7000
= 77000 mℓ

Volume of ⁴₅ of the tank
= 77000 + 1512
= 78512 mℓ

Volume of the tank
= 78512 ÷ ⁴₅
= 78512 x ⁵₄
= 98140 mℓ

Base area
= 73 x 22
= 1606 cm² 

Height of the tank
= 98140 ÷ 1606
≈ 61.1 cm

Answer(s): 61.1 cm