Question 853232
Let the number of passes be "x", so the cost of all the passes will be 4.50x
The museum makes at least 7200, which means it had to at least equal to 7200, or it can be more than 7200. Therefore, we have an inequality:

{{{4.50x >= 7200}}}  
{{{x >= 7200/4.5}}}
{{{x >= 1600}}}
So 1600 passes must be sold for the museum to make at least 7200.
TA-DAH 
:D