PSLE
Mrs Heng had a bottle of maple syrup. She used an equal amount of maple syrup each day. At the end of the sixth day, she had 630 mℓ of maple syrup left. At the end of the tenth day, she had one-third of the bottle of maple syrup left. How many litres of maple syrup were there in the bottle at first?
Fraction of maple syrup used after one-third of the bottle was left
= 1 - ¹₃
= ²₃

²₃ of the bottle → 10 days
1 bottle → 10 ÷ ²₃ = 10 x ³₂ =  15 days

It takes 15 days to finish the whole bottle.

Number of days to use 630 mℓ of maple syrup
= 15 - 6
= 9

9 days → 630 mℓ

1 day → 630 ÷ 9 = 70 mℓ

15 days → 15 x 70 = 1050 mℓ

1000 mℓ = 1 ℓ

1050 mℓ = 1050 ÷ 1000 = 1.05 ℓ

Volume of maple syrup in the bottle at first = 1.05 ℓ

Answer(s): 1.05 ℓ