A rectangular tank measuring 81 cm by 55 cm by 22 cm was to be filled with water by two taps, K and L. Tap K which fills the tank at a rate of 5 ℓ per minute was first turned on for 3 minutes before Tap L was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap K was first turned on, what is the rate at which Tap L fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 81 x 55 x 22
= 98010 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap K
= 5000 x 5
= 25000 cm
3 Volume of water filled by Tap L
= 98010 - 25000
= 73010 cm
3 Rate in which Tap L fills the tank
= 73010 ÷ 2
= 36505 cm3/min
36505 mℓ/min
= 36.505 ℓ/min
≈ 36.5 ℓ/min (Correct to 1 decimal place)
Answer(s): 36.5 ℓ/min