An empty rectangular tank has a capacity of 51 ℓ and a height of 100 cm. At 6 a.m., Tap G is turned on to fill the tank at a rate of 8 ℓ per minute for 19 minutes. After 15 minutes, Tap H is turned on to drain water from the tank at a rate of 4 ℓ per minute for 15 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 
8 ℓ = 8000 cm³ 
4 ℓ = 4000 cm³ 
51 ℓ = 51000 cm³

Volume of water flowed in from Tap G
= 19 x 8000
= 152000 cm³

Volume of water from drained from Tap H
= 15 x 4000
= 60000 cm³

Volume of water left in the tank
= 152000 - 60000
= 92000 cm³

Base area of the tank
= 51000 ÷ 100
= 510 cm² 

Height of water left in the tank
= 92000 ÷ 510
≈ 180.4 cm

Answer(s): 180.4 cm