Usha purchased a bottle of oil. She used ⁵₈ of the oil in March. She then used the remaining oil in April and May in the ratio 4 : 9. Given that the amount of the oil used in May was 0.76 ℓ less than that in March, how many millilitres of oil did the bottle contain at first?

March	April	May	Total
5x13	3x13		8x13
	4x3	9x3
65 u	12 u	27 u	104 u

Total volume of April and May is combined repeated identity. Make the total volume of April and May the same. LCM of 3 and 13 is 39.

Volume of less oil syrup in the bottle used in May than March
= 65 u - 27 u
= 38 u

38 u = 0.76 

1 u = 0.76 ÷ 38 = 0.02

Amount of oil in the bottle at first
= 104 u
= 104 x 0.02
= 2.08 ℓ

1 ℓ = 1000 mℓ

Amount of oil in the bottle at first
= 2.08 x 1000
= 2080 mℓ

Answer(s): 2080 mℓ