The figure shows a container made up of 3 sections. Cuboid C with a square base of side 14 cm and height 28 cm. Cube D with a side of 11 cm. Cuboid E that is 61 cm by 17 cm by 41 cm. Water from a tap above flows down at a rate of 3.3 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 61 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of D
= 11 x 11 x 11
= 1331 cm³ 

Volume of E
= 61 x 17 x 41
= 42517 cm³ 

2 ℓ = 2000 cm³ 
3.3 ℓ = 3300 cm³ 

Net increase in volume per minute
= 3300 - 2000
= 1300 cm³/min

Height of C to be filled with water
= 61 - (41 + 11)
= 9 cm

Volume of water in C
= 14 x 14 x 9
= 1764 cm³ 

Volume of water in E, D and part of C
= 42517 + 1331 + 1764
= 45612 cm³ 

Time taken to reach height
= 45612 ÷ 1300
≈ 35 min (Correct to nearest whole number)

Answer(s): 35 min