Opal purchased a bottle of peach syrup to make drinks. She used ³₅ of the syrup in April. She then used the remaining syrup in May and June in the ratio 1 : 4. Given that the amount of the peach syrup used in April was 1.56 ℓ more than that in May, how many millilitres of peach syrup did the bottle contain at first?

April	May	June	Total
3x5	2x5		5x5
	1x2	4x2
15 u	2 u	8 u	25 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 5 is 10.

Volume of more peach syrup in the bottle used in April than May
= 15 u - 2 u
= 13 u

13 u = 1.56 

1 u = 1.56 ÷ 13 = 0.12

Amount of peach syrup in the bottle at first
= 25 u
= 25 x 0.12
= 3 ℓ

1 ℓ = 1000 mℓ

Amount of peach syrup in the bottle at first
= 3 x 1000
= 3000 mℓ

Answer(s): 3000 mℓ