Rael has 2 containers. Container K and Container L are of different capacities. If Container K is filled by a tap at a rate of 3 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, 5 litres of water flowed out from Container L. If Container K is filled by a tap at a rate of 6 litres per minute and Container L is filled by a tap at a rate of 5 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	3 u	7 u - 5	6 p	5 p x 2 = 10 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)
7 u - 5 = 10 p
7 u = 10 p + 5 --- (2)

Make u the same.

(1) x 7
21 u = 42 p --- (3)

(2) x 3
21 u = 30 p + 15 --- (4)

(3) = (4)
42 p = 30 p + 15
42 p - 30 p = 15
12 p = 15
1 p = 15 ÷ 12 = 1.25

Volume of Container L
= 10 p
= 10 x 1.25
= 12.5 ℓ

Answer(s): 12.5 ℓ