To find the inequality that represents all possible values of \( p \), the number of pounds of oranges Devin can buy, we start with the information provided:
- Devin has $20.
- The cost of oranges is $2.50 per pound.
The total cost of the oranges can be expressed as \( 2.50p \), where \( p \) is the number of pounds. Devin needs to ensure that the total cost does not exceed the amount of money he has (which is $20). Therefore, we can set up the following inequality:
\[ 2.50p \leq 20 \]
This inequality indicates that Devin can buy any number of pounds of oranges as long as the total cost is less than or equal to $20.
To solve for \( p \), we can divide both sides of the inequality by \( 2.50 \):
\[ p \leq \frac{20}{2.50} \]
Calculating the right side:
\[ \frac{20}{2.50} = 8 \]
Thus, the inequality representing all possible values of \( p \) is:
\[ p \leq 8 \]
This means Devin can buy up to 8 pounds of oranges without exceeding his budget.