When Shiva was born, his father's age was 32 years. When his brother, who is 4…

Concept:

When two people's ages are given at different points in time (for example, at different children's births), the difference between their ages stays constant over time -- it never changes, because both people age at the same rate. To compare their ages, first bring both given ages to the SAME reference point in time using any stated age gaps, then subtract.

Application:

1. Shiva's brother is 4 years younger than Shiva, so the brother was born exactly 4 years after Shiva.

2. At the brother's birth, the mother's age was 30 years. Four years earlier, at Shiva's birth, the mother's age was 30 - 4 = 26 years.

3. At Shiva's birth, the father's age was 32 years (given directly).

4. The difference between the parents' ages at Shiva's birth = 32 - 26 = 6 years.

Cross-check:

Using the brother's birth as the reference point instead: the father's age there would be 32 + 4 = 36 years, and the mother's age is given as 30 years, so the difference is 36 - 30 = 6 years -- the same result, confirming the age difference between the parents is constant at 6 years.

Answer: 6 years