An empty rectangular container has a capacity of 129 ℓ and a height of 75 cm. At 6 a.m., Tap W is turned on to fill the container at a rate of 6 ℓ per minute for 17 minutes. After 12 minutes, Tap X is turned on to drain water from the container at a rate of 3 ℓ per minute for 14 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 
6 ℓ = 6000 cm³ 
3 ℓ = 3000 cm³ 
129 ℓ = 129000 cm³

Volume of water flowed in from Tap W
= 17 x 6000
= 102000 cm³

Volume of water from drained from Tap X
= 14 x 3000
= 42000 cm³

Volume of water left in the container
= 102000 - 42000
= 60000 cm³

Base area of the container
= 129000 ÷ 75
= 1720 cm² 

Height of water left in the container
= 60000 ÷ 1720
≈ 34.9 cm

Answer(s): 34.9 cm