5 identical 10-cm cubes are placed in an empty rectangular tank of length 77 cm and width 21 cm. The tank is then filled with water from a tap flowing at a rate of 10 litres per minute. It takes 13 minutes to fill up ¹₅ of the tank. What is the height of the tank? Correct your answer to 1 decimal place.
Volume of 1 cube
= 10 x 10 x 10
= 1000 cm³ 

Volume of 5 cubes
= 5 x 1000
= 5000 cm³ 

1 ℓ = 1000 mℓ
10 ℓ = 10000 mℓ

Volume of water in the tank
= 13 x 10000
= 130000 mℓ

Volume of ¹₅ of the tank
= 130000 + 5000
= 135000 mℓ

Volume of the tank
= 135000 ÷ ¹₅
= 135000 x ⁵₁
= 675000 mℓ

Base area
= 77 x 21
= 1617 cm² 

Height of the tank
= 675000 ÷ 1617
≈ 417.4 cm

Answer(s): 417.4 cm