PSLE
Mrs Leng had a bottle of maple syrup. She used an equal amount of maple syrup each day. At the end of the seventh day, she had 500 mℓ of maple syrup left. At the end of the ninth day, she had one-quarter 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-quarter of the bottle was left
= 1 - ¹₄
= ³₄

³₄ of the bottle → 9 days
1 bottle → 9 ÷ ³₄ = 9 x ⁴₃ =  12 days

It takes 12 days to finish the whole bottle.

Number of days to use 500 mℓ of maple syrup
= 12 - 7
= 5

5 days → 500 mℓ

1 day → 500 ÷ 5 = 100 mℓ

12 days → 12 x 100 = 1200 mℓ

1000 mℓ = 1 ℓ

1200 mℓ = 1200 ÷ 1000 = 1.2 ℓ

Volume of maple syrup in the bottle at first = 1.2 ℓ

Answer(s): 1.2 ℓ