If a = 4, b = 6 and c = 3, then a(b - c)/b(a + b + c) =?

Question: If a = 4, b = 6 and c = 3, then a(b - c)/b(a + b + c) =?

Solution:
Given that,
a = 4, b = 6 and c = 3

Now,
a(b - c)/b(a + b + c)
= 4(6 - 3)/6(4 + 6 + 3)
= 12/78
= 2/13