An empty rectangular tank has a capacity of 72 ℓ and a height of 40 cm. At 7 a.m., Tap T is turned on to fill the tank at a rate of 10 ℓ per minute for 15 minutes. After 3 minutes, Tap U is turned on to drain water from the tank at a rate of 6 ℓ per minute for 6 minutes. What is the height of the water level in the tank in the end? Give the answer in 1 decimal place.
1 ℓ = 1000 cm³ 
10 ℓ = 10000 cm³ 
6 ℓ = 6000 cm³ 
72 ℓ = 72000 cm³

Volume of water flowed in from Tap T
= 15 x 10000
= 150000 cm³

Volume of water from drained from Tap U
= 6 x 6000
= 36000 cm³

Volume of water left in the tank
= 150000 - 36000
= 114000 cm³

Base area of the tank
= 72000 ÷ 40
= 1800 cm² 

Height of water left in the tank
= 114000 ÷ 1800
≈ 63.3 cm

Answer(s): 63.3 cm