8 identical 7-cm cubes are placed in an empty rectangular tank of length 74 cm and width 30 cm. The tank is then filled with water from a tap flowing at a rate of 10 litres per minute. It takes 14 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
= 7 x 7 x 7
= 343 cm³ 

Volume of 8 cubes
= 8 x 343
= 2744 cm³ 

1 ℓ = 1000 mℓ
10 ℓ = 10000 mℓ

Volume of water in the tank
= 14 x 10000
= 140000 mℓ

Volume of ⁴₅ of the tank
= 140000 + 2744
= 142744 mℓ

Volume of the tank
= 142744 ÷ ⁴₅
= 142744 x ⁵₄
= 178430 mℓ

Base area
= 74 x 30
= 2220 cm² 

Height of the tank
= 178430 ÷ 2220
≈ 80.4 cm

Answer(s): 80.4 cm