A rectangular tank measuring 72 cm by 51 cm by 32 cm was to be filled with water by two taps, W and X. Tap W which fills the tank at a rate of 5 ℓ per minute was first turned on for 3 minutes before Tap X was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap W was first turned on, what is the rate at which Tap X fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 72 x 51 x 32
= 117504 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap W
= 5000 x 5
= 25000 cm
3 Volume of water filled by Tap X
= 117504 - 25000
= 92504 cm
3 Rate in which Tap X fills the tank
= 92504 ÷ 2
= 46252 cm3/min
46252 mℓ/min
= 46.252 ℓ/min
≈ 46.3 ℓ/min (Correct to 1 decimal place)
Answer(s): 46.3 ℓ/min