The figure, not drawn to scale, shows an empty tank measuring 50 cm by 15 cm by 15 cm. Water flows from Tap X at a rate of 500 mℓ per minute and from Tap Y at a rate of 240 mℓ per minute. Tower Z and Tower A have a base area of 20 cm² and 80 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 tank
= 50 x 15 x 15
= 11250 cm³ 

Volume of water flow per minute
= 500 + 240 - 120
= 620 cm³/min

Volume of water flow in 19 minutes
= 19 x 620
= 11780 cm³ 

Volume of water in the 2 towers
= 11780 - 11250
= 530 cm³ 

Total combined base areas of 2 towers
= 20 + 80
= 100 cm² 

Height of water in 2 towers
= 530 ÷ 100
= 5.3 cm

Total height of water
= 5.3 + 15
= 20.3 cm

Answer(s): 20.3 cm