An empty rectangular container has a capacity of 122 ℓ and a height of 200 cm. At 8 a.m., Tap Q is turned on to fill the container at a rate of 6 ℓ per minute for 16 minutes. After 9 minutes, Tap R is turned on to drain water from the container at a rate of 2 ℓ per minute for 6 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 
6 ℓ = 6000 cm³ 
2 ℓ = 2000 cm³ 
122 ℓ = 122000 cm³

Volume of water flowed in from Tap Q
= 16 x 6000
= 96000 cm³

Volume of water from drained from Tap R
= 6 x 2000
= 12000 cm³

Volume of water left in the container
= 96000 - 12000
= 84000 cm³

Base area of the container
= 122000 ÷ 200
= 610 cm² 

Height of water left in the container
= 84000 ÷ 610
≈ 137.7 cm

Answer(s): 137.7 cm