The figure, not drawn to scale, shows an empty tank measuring 20 cm by 15 cm by 15 cm. Water flows from Tap S at a rate of 300 mℓ per minute and from Tap T at a rate of 160 mℓ per minute. Tower U and Tower V have a base area of 60 cm² and 80 cm² respectively. Water is drained out of the container at a rate of 150 mℓ per minute. Find the height of the water level after 17 minutes.
Volume of the tank
= 20 x 15 x 15
= 4500 cm³ 

Volume of water flow per minute
= 300 + 160 - 150
= 310 cm³/min

Volume of water flow in 17 minutes
= 17 x 310
= 5270 cm³ 

Volume of water in the 2 towers
= 5270 - 4500
= 770 cm³ 

Total combined base areas of 2 towers
= 60 + 80
= 140 cm² 

Height of water in 2 towers
= 770 ÷ 140
= 5.5 cm

Total height of water
= 5.5 + 15
= 20.5 cm

Answer(s): 20.5 cm