An empty rectangular tank has a capacity of 154 ℓ and a height of 55 cm. At 8 a.m., Tap D is turned on to fill the tank at a rate of 3 ℓ per minute for 17 minutes. After 9 minutes, Tap E is turned on to drain water from the tank at a rate of 4 ℓ per minute for 12 minutes. What is the height of the water level in the tank in the end? Give the answer in 1 decimal place.
1 ℓ = 1000 cm³ 
3 ℓ = 3000 cm³ 
4 ℓ = 4000 cm³ 
154 ℓ = 154000 cm³

Volume of water flowed in from Tap D
= 17 x 3000
= 51000 cm³

Volume of water from drained from Tap E
= 12 x 4000
= 48000 cm³

Volume of water left in the tank
= 51000 - 48000
= 3000 cm³

Base area of the tank
= 154000 ÷ 55
= 2800 cm² 

Height of water left in the tank
= 3000 ÷ 2800
≈ 1.1 cm

Answer(s): 1.1 cm