The figure shows a container made up of 3 sections. Cuboid S with a square base of side 9 cm and height 36 cm. Cube T with a side of 10 cm. Cuboid U that is 63 cm by 14 cm by 45 cm. Water from a tap above flows down at a rate of 2.7 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 65 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
= 63 x 14 x 45
= 39690 cm³ 

2 ℓ = 2000 cm³ 
2.7 ℓ = 2700 cm³ 

Net increase in volume per minute
= 2700 - 2000
= 700 cm³/min

Height of S to be filled with water
= 65 - (45 + 10)
= 10 cm

Volume of water in S
= 9 x 9 x 10
= 810 cm³ 

Volume of water in U, T and part of S
= 39690 + 1000 + 810
= 41500 cm³ 

Time taken to reach height
= 41500 ÷ 700
≈ 59 min (Correct to nearest whole number)

Answer(s): 59 min