Eva purchased a bottle of starfruit syrup to make drinks. She used ¹₃ of the syrup in January. She then used the remaining syrup in February and March in the ratio 1 : 10. Given that the amount of the starfruit syrup used in January was 0.36 ℓ more than that in February, how many millilitres of starfruit syrup did the bottle contain at first?

January	February	March	Total
1x11	2x11		3x11
	1x2	10x2
11 u	2 u	20 u	33 u

Total volume of February and March is combined repeated identity.  Make the total volume of February and March the same.  LCM of 2 and 11 is 22.

Volume of more starfruit syrup in the bottle used in January than February
= 11 u - 2 u
= 9 u

9 u = 0.36 

1 u = 0.36 ÷ 9 = 0.04

Amount of starfruit syrup in the bottle at first
= 33 u
= 33 x 0.04
= 1.32 ℓ

1 ℓ = 1000 mℓ

Amount of starfruit syrup in the bottle at first
= 1.32 x 1000
= 1320 mℓ

Answer(s): 1320 mℓ