Risa and Gabby have $312. Barbara and Risa have $352. The ratio of Gabby to Barbara is 3 : 5. How much does Risa have?
Amount that Gabby has = 3 u
Amount that Barbara has = 5 u
The amount that Risa has is the repeated identity.
Risa + 3 u = 312 --- (1)
Risa + 5 u = 352 --- (2)
(2) - (1)
5 u - 3 u = 352 - 312
2 u = 40
1 u = 40 ÷ 2 = 20
From (1):
Risa + 3 u = 312
Risa + 3 x 20 = 312
Risa + 60 = 312
Amount that Risa has
= 312 - 60
= $252
Answer(s): $252
