PSLE
Nora had a bottle of coffee. She drank 500 mℓ of coffee in the morning and ³₅ of remaining coffee in the evening. After that, there was ¹₅ a bottle of coffee left. How much of the coffee did she drink in the evening?
Fraction of the remaining coffee left in the end
= 1 - ³₅
= ²₅

The remaining coffee left in the end is equal to ¹₅ of the bottle of coffee.
Make numerators the same.
LCM of 2 and 1 is 2.
 
²₅ of the remaining coffee = ¹₅ of the total coffee
²₅ of the remaining coffee = ²₁₀ of the total coffee

Volume of coffee that she drank in the morning
= 10 u - 5 u
= 5 u

5 u = 500

1 u = 500 ÷ 5 = 100

Volume of coffee that she drank in the evening
= 3 u
= 3 x 100
= 300 mℓ

Answer(s): 300 mℓ