The figure, not drawn to scale, shows an empty tank measuring 20 cm by 25 cm by 20 cm. Water flows from Tap S at a rate of 500 mℓ per minute and from Tap T at a rate of 240 mℓ per minute. Tower U and Tower V have a base area of 40 cm² and 20 cm² respectively. Water is drained out of the container at a rate of 130 mℓ per minute. Find the height of the water level after 19 minutes.
Volume of the tank
= 20 x 25 x 20
= 10000 cm³ 

Volume of water flow per minute
= 500 + 240 - 130
= 610 cm³/min

Volume of water flow in 19 minutes
= 19 x 610
= 11590 cm³ 

Volume of water in the 2 towers
= 11590 - 10000
= 1590 cm³ 

Total combined base areas of 2 towers
= 40 + 20
= 60 cm² 

Height of water in 2 towers
= 1590 ÷ 60
= 26.5 cm

Total height of water
= 26.5 + 20
= 46.5 cm

Answer(s): 46.5 cm