A rectangular tank measuring 73 cm by 50 cm by 40 cm was to be filled with water by two taps, B and C. Tap B which fills the tank at a rate of 9 ℓ per minute was first turned on for 2 minutes before Tap C was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap B was first turned on, what is the rate at which Tap C fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 73 x 50 x 40
= 146000 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap B
= 9000 x 7
= 63000 cm
3 Volume of water filled by Tap C
= 146000 - 63000
= 83000 cm
3 Rate in which Tap C fills the tank
= 83000 ÷ 5
= 16600 cm3/min
16600 mℓ/min
= 16.6 ℓ/min
≈ 16.6 ℓ/min (Correct to 1 decimal place)
Answer(s): 16.6 ℓ/min