The figure shows a container made up of 3 sections. Cuboid E with a square base of side 4 cm and height 33 cm. Cube F with a side of 16 cm. Cuboid G that is 61 cm by 10 cm by 43 cm. Water from a tap above flows down at a rate of 3.6 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 66 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of F
= 16 x 16 x 16
= 4096 cm³ 

Volume of G
= 61 x 10 x 43
= 26230 cm³ 

2 ℓ = 2000 cm³ 
3.6 ℓ = 3600 cm³ 

Net increase in volume per minute
= 3600 - 2000
= 1600 cm³/min

Height of E to be filled with water
= 66 - (43 + 16)
= 7 cm

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

Volume of water in G, F and part of E
= 26230 + 4096 + 112
= 30438 cm³ 

Time taken to reach height
= 30438 ÷ 1600
≈ 19 min (Correct to nearest whole number)

Answer(s): 19 min