The figure shows a container made up of 3 sections. Cuboid U with a square base of side 14 cm and height 48 cm. Cube V with a side of 13 cm. Cuboid W that is 70 cm by 28 cm by 40 cm. Water from a tap above flows down at a rate of 2.3 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 66 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of V
= 13 x 13 x 13
= 2197 cm³ 

Volume of W
= 70 x 28 x 40
= 78400 cm³ 

2 ℓ = 2000 cm³ 
2.3 ℓ = 2300 cm³ 

Net increase in volume per minute
= 2300 - 2000
= 300 cm³/min

Height of U to be filled with water
= 66 - (40 + 13)
= 13 cm

Volume of water in U
= 14 x 14 x 13
= 2548 cm³ 

Volume of water in W, V and part of U
= 78400 + 2197 + 2548
= 83145 cm³ 

Time taken to reach height
= 83145 ÷ 300
≈ 277 min (Correct to nearest whole number)

Answer(s): 277 min