Chapter 3 - Solving Inequalities - 3-1 Inequalities and Their Graphs - Practice and Problem-Solving Exercises - Page 168: 35

$p\leq172$

The key statement is, "the restaurant can seat at most 172 people." This can be interpreted as the restaurant can seat less than 172 people, but no more than 172 people, so the correct sign would be less than or equal to ($\leq$). Let $p$ be the number of people, so $p\leq172$, which is the correct inequality for this scenario.