Betty and Irene have $117. Risa and Betty have $165. The ratio of Irene to Risa is 1 : 4. How much does Betty have?
Amount that Irene has = 1 u
Amount that Risa has = 4 u
The amount that Betty has is the repeated identity.
Betty + 1 u = 117 --- (1)
Betty + 4 u = 165 --- (2)
(2) - (1)
4 u - 1 u = 165 - 117
3 u = 48
1 u = 48 ÷ 3 = 16
From (1):
Betty + 1 u = 117
Betty + 1 x 16 = 117
Betty + 16 = 117
Amount that Betty has
= 117 - 16
= $101
Answer(s): $101
