Final answer:
To find the greatest amount of $0.37 stamps Sandy could have purchased, subtract the cost of the package she mailed from the amount of money she had. Divide the result by the cost of the $0.37 stamp to find the maximum number she could buy.
Step-by-step explanation:
To find the greatest amount of $0.37 stamps Sandy could have purchased, we need to subtract the cost of the package she mailed from the amount of money she had. The inequality can be written as:
20 - 3.67 ≥ 0.37n
Simplifying the equation, we have:
16.33 ≥ 0.37n
To solve for n, we divide both sides of the inequality by 0.37:
44.1 ≥ n
Therefore, the greatest amount of $0.37 stamps Sandy could have purchased is 44 or less.