PSLE
Mrs Peh had a bottle of maple syrup. She used an equal amount of maple syrup each day. At the end of the eighth day, she had 3200 mℓ of maple syrup left. At the end of the tenth day, she had three-quarters 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 three-quarters of the bottle was left
= 1 - ³₄
= ¹₄

¹₄ of the bottle → 10 days
1 bottle → 10 ÷ ¹₄ = 10 x ⁴₁ =  40 days

It takes 40 days to finish the whole bottle.

Number of days to use 3200 mℓ of maple syrup
= 40 - 8
= 32

32 days → 3200 mℓ

1 day → 3200 ÷ 32 = 100 mℓ

40 days → 40 x 100 = 4000 mℓ

1000 mℓ = 1 ℓ

4000 mℓ = 4000 ÷ 1000 = 4 ℓ

Volume of maple syrup in the bottle at first = 4 ℓ

Answer(s): 4 ℓ