Aby and his brother Ben are teenagers.
13 ≤ A ≤ 19, 13 ≤ B ≤ 19
Ben is 3 years younger than Aby
B = A-3, so we substitute A-3 for B and
13 ≤ B ≤ 19 becomes
13 ≤ A-3 ≤ 19
We add 3 to all three sides:
16 ≤ A ≤ 22, but since A ≤ 19,
16 ≤ A ≤ 19
the GCF of their age is 3
So A is a multiple of 3 and the only multiple of 3
between 16 and 19 is 18, so
A = 18 and B = A-3 = 18-3 = 15.
Edwin
