A man's age is four times that of his son today. Five years ago, the man was nine times as old as his son was then. What is the man's present age?

Introduction / Context:
We combine a present multiplicative relation with a past multiplicative relation. Two equations in two unknowns lead to the solution.

Given Data / Assumptions:

• Present: Man = 4 × Son
• Five years ago: Man − 5 = 9 × (Son − 5)

Concept / Approach:
Let present ages be M and S. Use the present relation to substitute into the past relation and solve.

Step-by-Step Solution:

Verification / Alternative check:

Why Other Options Are Wrong:

• 24, 40, 44 do not satisfy both the present and past multiplicative relations.
• None of these: 32 meets all conditions.

Common Pitfalls:
Applying the 4× factor to past ages instead of present; or forgetting to subtract 5 from both ages in the past relation.

Final Answer:
32 years