An empty rectangular container has a capacity of 87 ℓ and a height of 25 cm. At 9 a.m., Tap W is turned on to fill the container at a rate of 10 ℓ per minute for 17 minutes. After 6 minutes, Tap X is turned on to drain water from the container at a rate of 4 ℓ per minute for 30 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 
10 ℓ = 10000 cm³ 
4 ℓ = 4000 cm³ 
87 ℓ = 87000 cm³

Volume of water flowed in from Tap W
= 17 x 10000
= 170000 cm³

Volume of water from drained from Tap X
= 30 x 4000
= 120000 cm³

Volume of water left in the container
= 170000 - 120000
= 50000 cm³

Base area of the container
= 87000 ÷ 25
= 3480 cm² 

Height of water left in the container
= 50000 ÷ 3480
≈ 14.4 cm

Answer(s): 14.4 cm