Mary and Diana have $238. Marion and Mary have $286. The ratio of Diana to Marion is 1 : 4. How much does Mary have?
Amount that Diana has = 1 u
Amount that Marion has = 4 u
The amount that Mary has is the repeated identity.
Mary + 1 u = 238 --- (1)
Mary + 4 u = 286 --- (2)
(2) - (1)
4 u - 1 u = 286 - 238
3 u = 48
1 u = 48 ÷ 3 = 16
From (1):
Mary + 1 u = 238
Mary + 1 x 16 = 238
Mary + 16 = 238
Amount that Mary has
= 238 - 16
= $222
Answer(s): $222
