Aubrey has 2 tanks. Tank H and Tank J are of different capacities. If Tank H is filled by a tap at a rate of 3 litres per minute and Tank J is filled by a tap at a rate of 7 litres per minute, when Tank H is completely filled, 8 litres of water flowed out from Tank J. If Tank H is filled by a tap at a rate of 3 litres per minute and Tank J is filled by a tap at a rate of 3 litres per minute, when Tank H is completely filled, Tank J is only half-filled. What is the capacity of Tank J? Express your answer in litres.

	Scenario 1		Scenario 2
Tank type	Tank H	Tank J	Tank H	Tank J
Volume of the tank	3 u	7 u - 8	3 p	3 p x 2 = 6 p

Let 1 u be the time taken for Scenario 1.
Let 1 p be the time taken for Scenario 2.

3 u = 3 p --- (1)
7 u - 8 = 6 p
7 u = 6 p + 8 --- (2)

Make u the same.

(1) x 7
21 u = 21 p --- (3)

(2) x 3
21 u = 18 p + 24 --- (4)

(3) = (4)
21 p = 18 p + 24
21 p - 18 p = 24
3 p = 24
1 p = 24 ÷ 3 = 8

Volume of Tank J
= 6 p
= 6 x 8
= 48 ℓ

Answer(s): 48 ℓ