The figure shows a container made up of 3 sections. Cuboid V with a square base of side 25 cm and height 45 cm. Cube W with a side of 10 cm. Cuboid X that is 77 cm by 17 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 1 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 W
= 10 x 10 x 10
= 1000 cm³ 

Volume of X
= 77 x 17 x 47
= 61523 cm³ 

1 ℓ = 1000 cm³ 
2.4 ℓ = 2400 cm³ 

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

Height of V to be filled with water
= 63 - (47 + 10)
= 6 cm

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

Volume of water in X, W and part of V
= 61523 + 1000 + 3750
= 66273 cm³ 

Time taken to reach height
= 66273 ÷ 1400
≈ 47 min (Correct to nearest whole number)

Answer(s): 47 min