The figure shows a container made up of 3 sections. Cuboid S with a square base of side 25 cm and height 28 cm. Cube T with a side of 10 cm. Cuboid U that is 76 cm by 27 cm by 49 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 67 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of T
= 10 x 10 x 10
= 1000 cm³ 

Volume of U
= 76 x 27 x 49
= 100548 cm³ 

2 ℓ = 2000 cm³ 
2.3 ℓ = 2300 cm³ 

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

Height of S to be filled with water
= 67 - (49 + 10)
= 8 cm

Volume of water in S
= 25 x 25 x 8
= 5000 cm³ 

Volume of water in U, T and part of S
= 100548 + 1000 + 5000
= 106548 cm³ 

Time taken to reach height
= 106548 ÷ 300
≈ 355 min (Correct to nearest whole number)

Answer(s): 355 min