The figure shows a container made up of 3 sections. Cuboid A with a square base of side 25 cm and height 33 cm. Cube B with a side of 10 cm. Cuboid C that is 68 cm by 17 cm by 48 cm. Water from a tap above flows down at a rate of 2.5 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 B
= 10 x 10 x 10
= 1000 cm³ 

Volume of C
= 68 x 17 x 48
= 55488 cm³ 

2 ℓ = 2000 cm³ 
2.5 ℓ = 2500 cm³ 

Net increase in volume per minute
= 2500 - 2000
= 500 cm³/min

Height of A to be filled with water
= 67 - (48 + 10)
= 9 cm

Volume of water in A
= 25 x 25 x 9
= 5625 cm³ 

Volume of water in C, B and part of A
= 55488 + 1000 + 5625
= 62113 cm³ 

Time taken to reach height
= 62113 ÷ 500
≈ 124 min (Correct to nearest whole number)

Answer(s): 124 min