PSLE
Tina had a bottle of soy milk. She drank 1160 mℓ of soy milk in the afternoon and ³₇ of remaining soy milk in the evening. After that, there was ¹₉ a bottle of soy milk left. How much of the soy milk did she drink in the evening?
Fraction of the remaining soy milk left in the end
= 1 - ³₇
= ⁴₇

The remaining soy milk left in the end is equal to ¹₉ of the bottle of soy milk.
Make numerators the same.
LCM of 4 and 1 is 4.
 
⁴₇ of the remaining soy milk = ¹₉ of the total soy milk
⁴₇ of the remaining soy milk = ⁴₃₆ of the total soy milk

Volume of soy milk that she drank in the afternoon
= 36 u - 7 u
= 29 u

29 u = 1160

1 u = 1160 ÷ 29 = 40

Volume of soy milk that she drank in the evening
= 3 u
= 3 x 40
= 120 mℓ

Answer(s): 120 mℓ