The figure shows a container made up of 3 sections. Cuboid H with a square base of side 14 cm and height 31 cm. Cube J with a side of 13 cm. Cuboid K that is 70 cm by 19 cm by 47 cm. Water from a tap above flows down at a rate of 2.4 litres per minute while water is drained out from the bottom at a rate of 2 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
= 13 x 13 x 13
= 2197 cm³ 

Volume of K
= 70 x 19 x 47
= 62510 cm³ 

2 ℓ = 2000 cm³ 
2.4 ℓ = 2400 cm³ 

Net increase in volume per minute
= 2400 - 2000
= 400 cm³/min

Height of H to be filled with water
= 70 - (47 + 13)
= 10 cm

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

Volume of water in K, J and part of H
= 62510 + 2197 + 1960
= 66667 cm³ 

Time taken to reach height
= 66667 ÷ 400
≈ 167 min (Correct to nearest whole number)

Answer(s): 167 min