An empty rectangular container has a capacity of 82 ℓ and a height of 16 cm. At 8 a.m., Tap B is turned on to fill the container at a rate of 8 ℓ per minute for 17 minutes. After 12 minutes, Tap C is turned on to drain water from the container at a rate of 2 ℓ per minute for 15 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 
8 ℓ = 8000 cm³ 
2 ℓ = 2000 cm³ 
82 ℓ = 82000 cm³

Volume of water flowed in from Tap B
= 17 x 8000
= 136000 cm³

Volume of water from drained from Tap C
= 15 x 2000
= 30000 cm³

Volume of water left in the container
= 136000 - 30000
= 106000 cm³

Base area of the container
= 82000 ÷ 16
= 5125 cm² 

Height of water left in the container
= 106000 ÷ 5125
≈ 20.7 cm

Answer(s): 20.7 cm