A mother is twice as old as her son. If 20 years ago, the age of the mother was 10 times the age of the son, what is the present age of the mother in years?

45

Let the age of the mother be M and that of her son be S. So, according to the question:

M = 2S ----------(1)

20 years ago: M = 10S, i.e. M - 20 = 10(S - 20) ----------(2)

Putting 1 in 2, we get:

2S - 20 = 10S - 200

8S = 180

S = \(\frac{ 180}{ 8}\)

S = 22.5

Age of mother is twice that of his son. So, mother's age is 45 years.