Solution:Let the age of father be X and the age of son be Y.According to the question.
(X – n) = Y
or X – Y = n (i)
and X = 4 (Y – n)
or X = 4Y – 4n
or (4Y – X)/4 = n (ii)
From equation (i) and (ii), we get:
X – Y = (4Y – X)/4
or 4X – 4Y = 4Y – X
or 5X = 8Y
or X/Y = 8/5
or we can say that, X = 8k and Y = 5k
Given that, X + Y = 130
or 8k + 5k = 130
or 13k = 130
or k = 10
Hence, age of father (X) = 8k = 80 years
and age of son (Y) = 5k = 50 years
Difference in their ages = 80 – 50 = 30 years