Tina purchased a bottle of guava syrup to make drinks. She used ²₅ of the syrup in January. She then used the remaining syrup in February and March in the ratio 1 : 9. Given that the amount of the guava syrup used in January was 0.51 ℓ more than that in February, how many millilitres of guava syrup did the bottle contain at first?

January	February	March	Total
2x10	3x10		5x10
	1x3	9x3
20 u	3 u	27 u	50 u

Total volume of February and March is combined repeated identity.  Make the total volume of February and March the same.  LCM of 3 and 10 is 30.

Volume of more guava syrup in the bottle used in January than February
= 20 u - 3 u
= 17 u

17 u = 0.51 

1 u = 0.51 ÷ 17 = 0.03

Amount of guava syrup in the bottle at first
= 50 u
= 50 x 0.03
= 1.5 ℓ

1 ℓ = 1000 mℓ

Amount of guava syrup in the bottle at first
= 1.5 x 1000
= 1500 mℓ

Answer(s): 1500 mℓ