The figure shows a container made up of 3 sections. Cuboid J with a square base of side 4 cm and height 29 cm. Cube K with a side of 16 cm. Cuboid L that is 62 cm by 11 cm by 40 cm. Water from a tap above flows down at a rate of 3.2 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 63 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of K
= 16 x 16 x 16
= 4096 cm³ 

Volume of L
= 62 x 11 x 40
= 27280 cm³ 

2 ℓ = 2000 cm³ 
3.2 ℓ = 3200 cm³ 

Net increase in volume per minute
= 3200 - 2000
= 1200 cm³/min

Height of J to be filled with water
= 63 - (40 + 16)
= 7 cm

Volume of water in J
= 4 x 4 x 7
= 112 cm³ 

Volume of water in L, K and part of J
= 27280 + 4096 + 112
= 31488 cm³ 

Time taken to reach height
= 31488 ÷ 1200
≈ 26 min (Correct to nearest whole number)

Answer(s): 26 min