Emma and Risa have $234. Xuan and Emma have $258. The ratio of Risa to Xuan is 3 : 5. How much does Emma have?
Amount that Risa has = 3 u
Amount that Xuan has = 5 u
The amount that Emma has is the repeated identity.
Emma + 3 u = 234 --- (1)
Emma + 5 u = 258 --- (2)
(2) - (1)
5 u - 3 u = 258 - 234
2 u = 24
1 u = 24 ÷ 2 = 12
From (1):
Emma + 3 u = 234
Emma + 3 x 12 = 234
Emma + 36 = 234
Amount that Emma has
= 234 - 36
= $198
Answer(s): $198
