RIDDLE: Interview at Harvard University

Examine the following solution:
Let’s take a step-by-step approach to solving this issue.

Seven men are present.
The seven males each have seven wives.

Let’s first determine the total number of wives:
49 spouses come from 7 males × 7 wives / man.

Both men and wives now have seven children between them.

Since each of his seven wives has seven offspring, let’s figure out how many kids each man has overall:
49 offspring per man (7 wives × 7 children/wife).

Given that there are seven males, there are 343 children overall (7 men × 49 children/man).

Let’s finally tally up everyone:

49 spouses, 343 kids, 7 males

Thus, there are 399 people in all (7 + 49 + 343).

Therefore, there are 399 persons in all.