A rectangular tank measuring 79 cm by 55 cm by 34 cm was to be filled with water by two taps, W and X. Tap W which fills the tank at a rate of 7 ℓ per minute was first turned on for 4 minutes before Tap X was turned on as well. If the tank was filled to the brim in a total of 6 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
= 79 x 55 x 34
= 147730 cm
3 1 ℓ = 1000 cm
3 7 ℓ = 7000 cm
3 Volume of water filled by Tap W
= 7000 x 6
= 42000 cm
3 Volume of water filled by Tap X
= 147730 - 42000
= 105730 cm
3 Rate in which Tap X fills the tank
= 105730 ÷ 2
= 52865 cm3/min
52865 mℓ/min
= 52.865 ℓ/min
≈ 52.9 ℓ/min (Correct to 1 decimal place)
Answer(s): 52.9 ℓ/min