An empty rectangular container has a capacity of 198 ℓ and a height of 18 cm. At 10 a.m., Tap D is turned on to fill the container at a rate of 4 ℓ per minute for 18 minutes. After 13 minutes, Tap E is turned on to drain water from the container at a rate of 6 ℓ per minute for 10 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 
4 ℓ = 4000 cm³ 
6 ℓ = 6000 cm³ 
198 ℓ = 198000 cm³

Volume of water flowed in from Tap D
= 18 x 4000
= 72000 cm³

Volume of water from drained from Tap E
= 10 x 6000
= 60000 cm³

Volume of water left in the container
= 72000 - 60000
= 12000 cm³

Base area of the container
= 198000 ÷ 18
= 11000 cm² 

Height of water left in the container
= 12000 ÷ 11000
≈ 1.1 cm

Answer(s): 1.1 cm