An empty rectangular container has a capacity of 57 ℓ and a height of 30 cm. At 6 a.m., Tap H is turned on to fill the container at a rate of 3 ℓ per minute for 16 minutes. After 11 minutes, Tap J is turned on to drain water from the container at a rate of 4 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 
3 ℓ = 3000 cm³ 
4 ℓ = 4000 cm³ 
57 ℓ = 57000 cm³

Volume of water flowed in from Tap H
= 16 x 3000
= 48000 cm³

Volume of water from drained from Tap J
= 5 x 4000
= 20000 cm³

Volume of water left in the container
= 48000 - 20000
= 28000 cm³

Base area of the container
= 57000 ÷ 30
= 1900 cm² 

Height of water left in the container
= 28000 ÷ 1900
≈ 14.7 cm

Answer(s): 14.7 cm