The figure shows a container made up of 3 sections. Cuboid W with a square base of side 25 cm and height 41 cm. Cube X with a side of 11 cm. Cuboid Y that is 74 cm by 27 cm by 45 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 1 litre per minute. How long did it take to fill up the container to a height of 62 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of X
= 11 x 11 x 11
= 1331 cm³ 

Volume of Y
= 74 x 27 x 45
= 89910 cm³ 

1 ℓ = 1000 cm³ 
2.4 ℓ = 2400 cm³ 

Net increase in volume per minute
= 2400 - 1000
= 1400 cm³/min

Height of W to be filled with water
= 62 - (45 + 11)
= 6 cm

Volume of water in W
= 25 x 25 x 6
= 3750 cm³ 

Volume of water in Y, X and part of W
= 89910 + 1331 + 3750
= 94991 cm³ 

Time taken to reach height
= 94991 ÷ 1400
≈ 68 min (Correct to nearest whole number)

Answer(s): 68 min