An empty rectangular tank has a capacity of 71 ℓ and a height of 10 cm. At 9 a.m., Tap G is turned on to fill the tank at a rate of 10 ℓ per minute for 17 minutes. After 14 minutes, Tap H is turned on to drain water from the tank at a rate of 3 ℓ per minute for 22 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 
10 ℓ = 10000 cm³ 
3 ℓ = 3000 cm³ 
71 ℓ = 71000 cm³

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

Volume of water from drained from Tap H
= 22 x 3000
= 66000 cm³

Volume of water left in the tank
= 170000 - 66000
= 104000 cm³

Base area of the tank
= 71000 ÷ 10
= 7100 cm² 

Height of water left in the tank
= 104000 ÷ 7100
≈ 14.6 cm

Answer(s): 14.6 cm