A rectangular container measuring 87 cm by 58 cm by 36 cm was to be filled with water by two taps, U and V. Tap U which fills the tank at a rate of 6 ℓ per minute was first turned on for 3 minutes before Tap V was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap U was first turned on, what is the rate at which Tap V fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 87 x 58 x 36
= 181656 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap U
= 6000 x 7
= 42000 cm
3 Volume of water filled by Tap V
= 181656 - 42000
= 139656 cm
3 Rate in which Tap V fills the container
= 139656 ÷ 4
= 34914 cm3/min
34914 mℓ/min
= 34.914 ℓ/min
≈ 34.9 ℓ/min (Correct to 1 decimal place)
Answer(s): 34.9 ℓ/min