The figure shows a container made up of 3 sections. Cuboid G with a square base of side 9 cm and height 24 cm. Cube H with a side of 11 cm. Cuboid J that is 64 cm by 25 cm by 43 cm. Water from a tap above flows down at a rate of 2.3 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 69 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of H
= 11 x 11 x 11
= 1331 cm³ 

Volume of J
= 64 x 25 x 43
= 68800 cm³ 

1 ℓ = 1000 cm³ 
2.3 ℓ = 2300 cm³ 

Net increase in volume per minute
= 2300 - 1000
= 1300 cm³/min

Height of G to be filled with water
= 69 - (43 + 11)
= 15 cm

Volume of water in G
= 9 x 9 x 15
= 1215 cm³ 

Volume of water in J, H and part of G
= 68800 + 1331 + 1215
= 71346 cm³ 

Time taken to reach height
= 71346 ÷ 1300
≈ 55 min (Correct to nearest whole number)

Answer(s): 55 min