6 identical 6-cm cubes are placed in an empty rectangular tank of length 81 cm and width 22 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 ²₅ 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 6 cubes
= 6 x 216
= 1296 cm³ 

1 ℓ = 1000 mℓ
10 ℓ = 10000 mℓ

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

Volume of ²₅ of the tank
= 140000 + 1296
= 141296 mℓ

Volume of the tank
= 141296 ÷ ²₅
= 141296 x ⁵₂
= 353240 mℓ

Base area
= 81 x 22
= 1782 cm² 

Height of the tank
= 353240 ÷ 1782
≈ 198.2 cm

Answer(s): 198.2 cm