A rectangular tank measuring 80 cm by 75 cm by 21 cm was ¹₈ filled with water. Irene turned on a tap at 2.32 p.m. to fill more water into the tank. She turned off the tap at 2.47 p.m. The tank was ⁷₈ 
filled with water. Given that the water flowed out of the tap at the same rate, find the volume of water that flowed out of the tap in a minute. Give your answer in litres.
Volume of water in the tank at first
= ¹₈ x 80 x 75 x 21
= 15750 cm³

Volume of water in the tank in the end
= ⁷₈ x 80 x 75 x 21
= 110250 cm³

Volume of water added into the tank by the tap
= 110250 - 15750
= 94500 cm³

1000 mℓ = 1 ℓ
94500 mℓ = 94500 ÷ 1000 = 94.5 ℓ

From 2.32 p.m. to 2.47 p.m.: 15 min

Volume of water that flowed out of the tap in a minute
= 94.5 ÷ 15
= 6.3 ℓ 

Answer(s): 6.3 ℓ