The figure shows a container made up of 3 sections. Cuboid H with a square base of side 14 cm and height 35 cm. Cube J with a side of 10 cm. Cuboid K that is 65 cm by 16 cm by 43 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
= 10 x 10 x 10
= 1000 cm³ 

Volume of K
= 65 x 16 x 43
= 44720 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 - (43 + 10)
= 10 cm

Volume of water in H
= 14 x 14 x 10
= 1960 cm³ 

Volume of water in K, J and part of H
= 44720 + 1000 + 1960
= 47680 cm³ 

Time taken to reach height
= 47680 ÷ 1700
≈ 28 min (Correct to nearest whole number)

Answer(s): 28 min