A rectangular tank measuring 88 cm by 60 cm by 40 cm was to be filled with water by two taps, A and B. Tap A which fills the tank at a rate of 7 ℓ per minute was first turned on for 3 minutes before Tap B was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap A was first turned on, what is the rate at which Tap B fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 88 x 60 x 40
= 211200 cm
3 1 ℓ = 1000 cm
3 7 ℓ = 7000 cm
3 Volume of water filled by Tap A
= 7000 x 7
= 49000 cm
3 Volume of water filled by Tap B
= 211200 - 49000
= 162200 cm
3 Rate in which Tap B fills the tank
= 162200 ÷ 4
= 40550 cm3/min
40550 mℓ/min
= 40.55 ℓ/min
≈ 40.6 ℓ/min (Correct to 1 decimal place)
Answer(s): 40.6 ℓ/min