An empty rectangular container has a capacity of 103 ℓ and a height of 20 cm. At 7 a.m., Tap T is turned on to fill the container at a rate of 7 ℓ per minute for 18 minutes. After 6 minutes, Tap U is turned on to drain water from the container at a rate of 9 ℓ per minute for 5 minutes. What is the height of the water level in the container in the end? Give the answer in 1 decimal place.
1 ℓ = 1000 cm³ 
7 ℓ = 7000 cm³ 
9 ℓ = 9000 cm³ 
103 ℓ = 103000 cm³

Volume of water flowed in from Tap T
= 18 x 7000
= 126000 cm³

Volume of water from drained from Tap U
= 5 x 9000
= 45000 cm³

Volume of water left in the container
= 126000 - 45000
= 81000 cm³

Base area of the container
= 103000 ÷ 20
= 5150 cm² 

Height of water left in the container
= 81000 ÷ 5150
≈ 15.7 cm

Answer(s): 15.7 cm