Xylia purchased a bottle of oil. She used ²₅ of the oil in April. She then used the remaining oil in May and June in the ratio 7 : 10. Given that the amount of the oil used in June was 0.12 ℓ less than that in April, how many millilitres of oil did the bottle contain at first?

April	May	June	Total
2x17	3x17		5x17
	7x3	10x3
34 u	21 u	30 u	85 u

Total volume of May and June is combined repeated identity. Make the total volume of May and June the same. LCM of 3 and 17 is 51.

Volume of less oil syrup in the bottle used in June than April
= 34 u - 30 u
= 4 u

4 u = 0.12 

1 u = 0.12 ÷ 4 = 0.03

Amount of oil in the bottle at first
= 85 u
= 85 x 0.03
= 2.55 ℓ

1 ℓ = 1000 mℓ

Amount of oil in the bottle at first
= 2.55 x 1000
= 2550 mℓ

Answer(s): 2550 mℓ