Let Baichung's father's present age be x years
Given Baichung's father is 29 years older than Baichung
Hence Baichung's age is (x − 29) years
Baichung's grandfather is 26 years older than Baichung's father.
Hence Baichung's grandfather's age = (x + 26) years
Given sum of three ages = 135 years
∴ x + (x − 29) +(x + 26) = 135
3x − 3 = 135
3x = 135 + 3 = 138
∴ x = 46
Baichung's father's age = 46 years
Baichung's grandfather's age = (x + 26) = (46 + 26) = 72 years
Baichung's age = (x − 29) = (46 − 29) = 17 years