Jackson has 2 containers. Container K and Container L are of different capacities. If Container K is filled by a tap at a rate of 5 litres per minute and Container L is filled by a tap at a rate of 7 litres per minute, when Container K is completely filled, 8 litres of water flowed out from Container L. If Container K is filled by a tap at a rate of 4 litres per minute and Container L is filled by a tap at a rate of 2 litres per minute, when Container K is completely filled, Container L is only half-filled. What is the capacity of Container L? Express your answer in litres.

	Scenario 1		Scenario 2
Container type	Container K	Container L	Container K	Container L
Volume of the container	5 u	7 u - 8	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.

5 u = 4 p --- (1)
7 u - 8 = 4 p
7 u = 4 p + 8 --- (2)

Make u the same.

(1) x 7
35 u = 28 p --- (3)

(2) x 5
35 u = 20 p + 40 --- (4)

(3) = (4)
28 p = 20 p + 40
28 p - 20 p = 40
8 p = 40
1 p = 40 ÷ 8 = 5

Volume of Container L
= 4 p
= 4 x 5
= 20 ℓ

Answer(s): 20 ℓ