The figure shows a container made up of 3 sections. Cuboid C with a square base of side 25 cm and height 35 cm. Cube D with a side of 10 cm. Cuboid E that is 80 cm by 13 cm by 43 cm. Water from a tap above flows down at a rate of 3.4 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 D
= 10 x 10 x 10
= 1000 cm³ 

Volume of E
= 80 x 13 x 43
= 44720 cm³ 

1 ℓ = 1000 cm³ 
3.4 ℓ = 3400 cm³ 

Net increase in volume per minute
= 3400 - 1000
= 2400 cm³/min

Height of C to be filled with water
= 63 - (43 + 10)
= 10 cm

Volume of water in C
= 25 x 25 x 10
= 6250 cm³ 

Volume of water in E, D and part of C
= 44720 + 1000 + 6250
= 51970 cm³ 

Time taken to reach height
= 51970 ÷ 2400
≈ 22 min (Correct to nearest whole number)

Answer(s): 22 min