Mia has 2 tanks. Tank H and Tank J are of different capacities. If Tank H is filled by a tap at a rate of 4 litres per minute and Tank J is filled by a tap at a rate of 6 litres per minute, when Tank H is completely filled, 7 litres of water flowed out from Tank J. If Tank H is filled by a tap at a rate of 4 litres per minute and Tank J is filled by a tap at a rate of 2 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	4 u	6 u - 7	4 p	2 p x 2 = 4 p

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

4 u = 4 p --- (1)
6 u - 7 = 4 p
6 u = 4 p + 7 --- (2)

Make u the same.

(1) x 3
12 u = 12 p --- (3)

(2) x 2
12 u = 8 p + 14 --- (4)

(3) = (4)
12 p = 8 p + 14
12 p - 8 p = 14
4 p = 14
1 p = 14 ÷ 4 = 3.5

Volume of Tank J
= 4 p
= 4 x 3.5
= 14 ℓ

Answer(s): 14 ℓ