7 identical 3-cm cubes are placed in an empty rectangular container of length 81 cm and width 21 cm. The container is then filled with water from a tap flowing at a rate of 7 litres per minute. It takes 13 minutes to fill up ¹₅ of the container. What is the height of the container? Correct your answer to 1 decimal place.
Volume of 1 cube
= 3 x 3 x 3
= 27 cm³ 

Volume of 7 cubes
= 7 x 27
= 189 cm³ 

1 ℓ = 1000 mℓ
7 ℓ = 7000 mℓ

Volume of water in the container
= 13 x 7000
= 91000 mℓ

Volume of ¹₅ of the container
= 91000 + 189
= 91189 mℓ

Volume of the container
= 91189 ÷ ¹₅
= 91189 x ⁵₁
= 455945 mℓ

Base area
= 81 x 21
= 1701 cm² 

Height of the container
= 455945 ÷ 1701
≈ 268 cm

Answer(s): 268 cm