An empty rectangular tank has a capacity of 71 ℓ and a height of 20 cm. At 10 a.m., Tap M is turned on to fill the tank at a rate of 7 ℓ per minute for 20 minutes. After 5 minutes, Tap N is turned on to drain water from the tank at a rate of 2 ℓ per minute for 24 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 
7 ℓ = 7000 cm³ 
2 ℓ = 2000 cm³ 
71 ℓ = 71000 cm³

Volume of water flowed in from Tap M
= 20 x 7000
= 140000 cm³

Volume of water from drained from Tap N
= 24 x 2000
= 48000 cm³

Volume of water left in the tank
= 140000 - 48000
= 92000 cm³

Base area of the tank
= 71000 ÷ 20
= 3550 cm² 

Height of water left in the tank
= 92000 ÷ 3550
≈ 25.9 cm

Answer(s): 25.9 cm