Abi purchased a bottle of sauce. She used ⁵₉ of the sauce in April. She then used the remaining sauce in May and June in the ratio 3 : 7. Given that the amount of the sauce used in June was 0.55 ℓ less than that in April, how many millilitres of sauce did the bottle contain at first?

April	May	June	Total
5x5	4x5		9x5
	3x2	7x2
25 u	6 u	14 u	45 u

Total volume of May and June is combined repeated identity. Make the total volume of May and June the same. LCM of 4 and 10 is 20.

Volume of less sauce syrup in the bottle used in June than April
= 25 u - 14 u
= 11 u

11 u = 0.55 

1 u = 0.55 ÷ 11 = 0.05

Amount of sauce in the bottle at first
= 45 u
= 45 x 0.05
= 2.25 ℓ

1 ℓ = 1000 mℓ

Amount of sauce in the bottle at first
= 2.25 x 1000
= 2250 mℓ

Answer(s): 2250 mℓ