PSLE
Cindy had a bottle of orange juice. She drank 210 mℓ of orange juice in the afternoon and ²₇ of remaining orange juice at night. After that, there was ¹₂ a bottle of orange juice left. How much of the orange juice did she drink at night?
Fraction of the remaining orange juice left in the end
= 1 - ²₇
= ⁵₇

The remaining orange juice left in the end is equal to ¹₂ of the bottle of orange juice.
Make numerators the same.
LCM of 5 and 1 is 5.
 
⁵₇ of the remaining orange juice = ¹₂ of the total orange juice
⁵₇ of the remaining orange juice = ⁵₁₀ of the total orange juice

Volume of orange juice that she drank in the afternoon
= 10 u - 7 u
= 3 u

3 u = 210

1 u = 210 ÷ 3 = 70

Volume of orange juice that she drank at night
= 2 u
= 2 x 70
= 140 mℓ

Answer(s): 140 mℓ