3 identical 7-cm cubes are placed in an empty rectangular tank of length 72 cm and width 26 cm. The tank is then filled with water from a tap flowing at a rate of 6 litres per minute. It takes 14 minutes to fill up ³₅ 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 3 cubes
= 3 x 343
= 1029 cm³ 

1 ℓ = 1000 mℓ
6 ℓ = 6000 mℓ

Volume of water in the tank
= 14 x 6000
= 84000 mℓ

Volume of ³₅ of the tank
= 84000 + 1029
= 85029 mℓ

Volume of the tank
= 85029 ÷ ³₅
= 85029 x ⁵₃
= 141715 mℓ

Base area
= 72 x 26
= 1872 cm² 

Height of the tank
= 141715 ÷ 1872
≈ 75.7 cm

Answer(s): 75.7 cm