Çözüldü Age Problem

Adapted from one of ÖSYM exams:

John and James both of whom have an elder brother are talking:
John: The age difference between me and my brother is the same as the age difference between you and your brother.
James: When I was born your brother was 13 years old.
John: When I was born your brother was 7 years old.
If John is fifteen years old today, what will the sum of the ages of all of them be five years later?
A) 79
B) 82
C) 88
D) 94
E) 100

Today,
John = 15 ⇒ JaBr = 15 + 7 = 22
JoBr = 13 + 7 = 20
20 - 15 = 22 - James ⇒ James = 17
Sum of their ages after five years = 15 + 22 + 20 + 17 + 4·5 = 94.