Correct Answer - Option 3 : 58

The average age of Ramesh and Mahesh is 42.

Sum of ages of Ramesh and Mahesh = 84

Amit′s age + Mahesh′s age + Ramesh′s age = 108

Amit′s age = 108 – 84 = 24

Mahesh is three years younger than Amit,

Therefore, Mahesh′s age = 21

Ramesh′s age = 84 – 21 = 63

Ramesh′s age on 1^{st} January, 2010 is = 63 - 5 =** 58.**

Hence, the correct answer is** 58.**