Sonali is 40 years old and Nitya is 60 years old. How many years ago was the ratio of their ages 3 : 5 ?

10 years

Let us consider that ,

X years ago , ratio of ages of Sonali and Nitya is 3 : 5

According to question,

\(\frac{ 40 - X }{ 60 - X}\) = \(\frac{3}{5}\)

200 - 5X = 180 - 3X

20 = 2X

X = 10

So, 10 years ago , ratio of ages of Sonali and Nitya is 3 : 5 

The correct answer is option (2) : 10 years