The figure shows a container made up of 3 sections. Cuboid B with a square base of side 14 cm and height 38 cm. Cube C with a side of 12 cm. Cuboid D that is 73 cm by 20 cm by 48 cm. Water from a tap above flows down at a rate of 3.7 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 66 cm from the base? Give the answer in minutes correct to nearest whole number.
Volume of C
= 12 x 12 x 12
= 1728 cm³ 

Volume of D
= 73 x 20 x 48
= 70080 cm³ 

1 ℓ = 1000 cm³ 
3.7 ℓ = 3700 cm³ 

Net increase in volume per minute
= 3700 - 1000
= 2700 cm³/min

Height of B to be filled with water
= 66 - (48 + 12)
= 6 cm

Volume of water in B
= 14 x 14 x 6
= 1176 cm³ 

Volume of water in D, C and part of B
= 70080 + 1728 + 1176
= 72984 cm³ 

Time taken to reach height
= 72984 ÷ 2700
≈ 27 min (Correct to nearest whole number)

Answer(s): 27 min