The figure shows a container made up of 3 sections. Cuboid G with a square base of side 4 cm and height 32 cm. Cube H with a side of 14 cm. Cuboid J that is 80 cm by 14 cm by 44 cm. Water from a tap above flows down at a rate of 2.1 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 64 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of H
= 14 x 14 x 14
= 2744 cm³ 

Volume of J
= 80 x 14 x 44
= 49280 cm³ 

1 ℓ = 1000 cm³ 
2.1 ℓ = 2100 cm³ 

Net increase in volume per minute
= 2100 - 1000
= 1100 cm³/min

Height of G to be filled with water
= 64 - (44 + 14)
= 6 cm

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

Volume of water in J, H and part of G
= 49280 + 2744 + 96
= 52120 cm³ 

Time taken to reach height
= 52120 ÷ 1100
≈ 47 min (Correct to nearest whole number)

Answer(s): 47 min