Yoko purchased a bottle of detergent. She used ³₅ of the detergent in January. She then used the remaining detergent in February and March in the ratio 1 : 4. Given that the amount of the detergent used in March was 0.14 ℓ less than that in January, how many millilitres of detergent did the bottle contain at first?

January	February	March	Total
3x5	2x5		5x5
	1x2	4x2
15 u	2 u	8 u	25 u

Total volume of February and March is combined repeated identity. Make the total volume of February and March the same. LCM of 2 and 5 is 10.

Volume of less detergent syrup in the bottle used in March than January
= 15 u - 8 u
= 7 u

7 u = 0.14 

1 u = 0.14 ÷ 7 = 0.02

Amount of detergent in the bottle at first
= 25 u
= 25 x 0.02
= 0.5 ℓ

1 ℓ = 1000 mℓ

Amount of detergent in the bottle at first
= 0.5 x 1000
= 500 mℓ

Answer(s): 500 mℓ