The figure, not drawn to scale, shows an empty container measuring 20 cm by 20 cm by 20 cm. Water flows from Tap V at a rate of 500 mℓ per minute and from Tap W at a rate of 190 mℓ per minute. Tower X and Tower Y have a base area of 10 cm² and 40 cm² respectively. Water is drained out of the container at a rate of 120 mℓ per minute. Find the height of the water level after 19 minutes.
Volume of the container
= 20 x 20 x 20
= 8000 cm³ 

Volume of water flow per minute
= 500 + 190 - 120
= 570 cm³/min

Volume of water flow in 19 minutes
= 19 x 570
= 10830 cm³ 

Volume of water in the 2 towers
= 10830 - 8000
= 2830 cm³ 

Total combined base areas of 2 towers
= 10 + 40
= 50 cm² 

Height of water in 2 towers
= 2830 ÷ 50
= 56.6 cm

Total height of water
= 56.6 + 20
= 76.6 cm

Answer(s): 76.6 cm