Let \( x \) represent the number of pies the class sells. The total amount of money the class has for the trip can be expressed as the $75 the principal gave plus $5 times the number of pies sold. The total cost of the trip is $386.
The inequality representing this situation would be:
\[ 75 + 5x \geq 386 \]
This inequality states that the money from the principal and the money earned from selling pies should be greater than or equal to the total cost of the trip.