The figure shows a container made up of 3 sections. Cuboid H with a square base of side 4 cm and height 27 cm. Cube J with a side of 16 cm. Cuboid K that is 61 cm by 17 cm by 41 cm. Water from a tap above flows down at a rate of 2.7 litres per minute while water is drained out from the bottom at a rate of 1 litre per minute. How long did it take to fill up the container to a height of 63 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of J
= 16 x 16 x 16
= 4096 cm³ 

Volume of K
= 61 x 17 x 41
= 42517 cm³ 

1 ℓ = 1000 cm³ 
2.7 ℓ = 2700 cm³ 

Net increase in volume per minute
= 2700 - 1000
= 1700 cm³/min

Height of H to be filled with water
= 63 - (41 + 16)
= 6 cm

Volume of water in H
= 4 x 4 x 6
= 96 cm³ 

Volume of water in K, J and part of H
= 42517 + 4096 + 96
= 46709 cm³ 

Time taken to reach height
= 46709 ÷ 1700
≈ 27 min (Correct to nearest whole number)

Answer(s): 27 min