The figure shows a container made up of 3 sections. Cuboid H with a square base of side 25 cm and height 48 cm. Cube J with a side of 18 cm. Cuboid K that is 69 cm by 16 cm by 43 cm. Water from a tap above flows down at a rate of 2.6 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 70 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of J
= 18 x 18 x 18
= 5832 cm³ 

Volume of K
= 69 x 16 x 43
= 47472 cm³ 

1 ℓ = 1000 cm³ 
2.6 ℓ = 2600 cm³ 

Net increase in volume per minute
= 2600 - 1000
= 1600 cm³/min

Height of H to be filled with water
= 70 - (43 + 18)
= 9 cm

Volume of water in H
= 25 x 25 x 9
= 5625 cm³ 

Volume of water in K, J and part of H
= 47472 + 5832 + 5625
= 58929 cm³ 

Time taken to reach height
= 58929 ÷ 1600
≈ 37 min (Correct to nearest whole number)

Answer(s): 37 min