The figure, not drawn to scale, shows an empty tank measuring 20 cm by 20 cm by 15 cm. Water flows from Tap F at a rate of 500 mℓ per minute and from Tap G at a rate of 140 mℓ per minute. Tower H and Tower J have a base area of 60 cm² and 60 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 17 minutes.
Volume of the tank
= 20 x 20 x 15
= 6000 cm³ 

Volume of water flow per minute
= 500 + 140 - 130
= 510 cm³/min

Volume of water flow in 17 minutes
= 17 x 510
= 8670 cm³ 

Volume of water in the 2 towers
= 8670 - 6000
= 2670 cm³ 

Total combined base areas of 2 towers
= 60 + 60
= 120 cm² 

Height of water in 2 towers
= 2670 ÷ 120
= 22.25 cm

Total height of water
= 22.25 + 15
= 37.25 cm

Answer(s): 37.25 cm