Answer:
Ruby is 15, Jane is 17 and Nora is 20.
Explanation:
Let x represent the age of Ruby.
Jane: 2x - 13
Ruby: x
Nora: x + 5
52 = (x) + (2x - 13) + (x + 5)
52 = x + 2x - 13 + x + 5
52 + 13 - 5 = x + 2x + x
60 = 4x
x = 15
Jane:
2(15) -13
= 17
Nora:
(15) + 5
= 20