Salik has 2 tanks. Tank R and Tank S are of different capacities. If Tank R is filled by a tap at a rate of 3 litres per minute and Tank S is filled by a tap at a rate of 5 litres per minute, when Tank R is completely filled, 8 litres of water flowed out from Tank S. If Tank R is filled by a tap at a rate of 6 litres per minute and Tank S is filled by a tap at a rate of 2 litres per minute, when Tank R is completely filled, Tank S is only one-third-filled. What is the capacity of Tank S? Express your answer in litres.

	Scenario 1		Scenario 2
Tank type	Tank R	Tank S	Tank R	Tank S
Volume of the tank	3 u	5 u - 8	6 p	2 p x 3 = 6 p

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

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

Make u the same.

(1) x 5
15 u = 30 p --- (3)

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

(3) = (4)
30 p = 18 p + 24
30 p - 18 p = 24
12 p = 24
1 p = 24 ÷ 12 = 2

Volume of Tank S
= 6 p
= 6 x 2
= 12 ℓ

Answer(s): 12 ℓ