1.A mother is three times the age of her son. Five (5) years back the son was l/6’h the age of his father. If father is 5 years older than the mother, what is the age of the son.

The correct answer is (b) 12yrs.

Let $s$ be the son’s current age, $m$ be the mother’s current age, and $f$ be the father’s current age. We are given that $m = 3s$ and $f = m + 5 = 3s + 5$. We are also given that $s – 5 = \frac{1}{6}(f – 5)$. Substituting $f = 3s + 5$ into this equation, we get $s – 5 = \frac{1}{6}(3s + 5 – 5)$, which simplifies to $6s – 30 = 3s$. Solving for $s$, we get $s = 12$.

Here is a brief explanation of each option:

• Option (a): $10$ years. This is not possible, because $10$ is not a multiple of $3$.
• Option (b): $12$ years. This is the correct answer, as shown above.
• Option (c): $14$ years. This is not possible, because $14$ is not a multiple of $6$.
• Option (d): $15$ years. This is not possible, because $15$ is not a multiple of $3$.