To determine the number of pies \( p \) the class needs to sell to cover the cost of the field trip, we can set up an inequality based on the information provided.
- The total cost of the field trip is $386.
- The principal has already given the class $75.
- The remainder of the cost that needs to be covered by selling pies is therefore \( 386 - 75 = 311 \).
- Each pie sells for $5, so the revenue from selling \( p \) pies is \( 5p \).
To ensure that the money from the pies covers the remaining cost, we need the revenue from the pies to be greater than or equal to the remaining cost:
\[ 5p \geq 311 \]
This inequality can be used to find \( p \), the number of pies the class needs to sell to earn enough money for the field trip.