Diana purchased a bottle of passion fruit syrup to make drinks. She used ¹₃ of the syrup in April. She then used the remaining syrup in May and June in the ratio 1 : 6. Given that the amount of the passion fruit syrup used in April was 0.3 ℓ more than that in May, how many millilitres of passion fruit syrup did the bottle contain at first?

April	May	June	Total
1x7	2x7		3x7
	1x2	6x2
7 u	2 u	12 u	21 u

Total volume of May and June is combined repeated identity.  Make the total volume of May and June the same.  LCM of 2 and 7 is 14.

Volume of more passion fruit syrup in the bottle used in April than May
= 7 u - 2 u
= 5 u

5 u = 0.3 

1 u = 0.3 ÷ 5 = 0.06

Amount of passion fruit syrup in the bottle at first
= 21 u
= 21 x 0.06
= 1.26 ℓ

1 ℓ = 1000 mℓ

Amount of passion fruit syrup in the bottle at first
= 1.26 x 1000
= 1260 mℓ

Answer(s): 1260 mℓ