A rectangular tank measuring 70 cm by 59 cm by 20 cm was to be filled with water by two taps, D and E. Tap D which fills the tank at a rate of 5 ℓ per minute was first turned on for 4 minutes before Tap E was turned on as well. If the tank was filled to the brim in a total of 6 minutes from the time when Tap D was first turned on, what is the rate at which Tap E fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 70 x 59 x 20
= 82600 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap D
= 5000 x 6
= 30000 cm
3 Volume of water filled by Tap E
= 82600 - 30000
= 52600 cm
3 Rate in which Tap E fills the tank
= 52600 ÷ 2
= 26300 cm3/min
26300 mℓ/min
= 26.3 ℓ/min
≈ 26.3 ℓ/min (Correct to 1 decimal place)
Answer(s): 26.3 ℓ/min