The figure shows a container made up of 3 sections. Cuboid X with a square base of side 4 cm and height 49 cm. Cube Y with a side of 12 cm. Cuboid Z that is 69 cm by 18 cm by 47 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 2 litre per minute. How long did it take to fill up the container to a height of 67 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of Y
= 12 x 12 x 12
= 1728 cm³ 

Volume of Z
= 69 x 18 x 47
= 58374 cm³ 

2 ℓ = 2000 cm³ 
2.6 ℓ = 2600 cm³ 

Net increase in volume per minute
= 2600 - 2000
= 600 cm³/min

Height of X to be filled with water
= 67 - (47 + 12)
= 8 cm

Volume of water in X
= 4 x 4 x 8
= 128 cm³ 

Volume of water in Z, Y and part of X
= 58374 + 1728 + 128
= 60230 cm³ 

Time taken to reach height
= 60230 ÷ 600
≈ 100 min (Correct to nearest whole number)

Answer(s): 100 min