Final answer:
Alang can buy a maximum of 7 hamburgers.
Step-by-step explanation:
To find the maximum number of hamburgers Alang can buy if he decides to buy 15 drinks, we need to first calculate the total cost of the drinks. Since each drink costs $2.50 and he wants to buy 15 drinks, the total cost of the drinks would be $2.50 multiplied by 15, which gives us $37.50.
Next, we subtract the cost of the drinks from Alang's budget. Alang has $95, so by subtracting $37.50 from $95, we get $57.50.
Now, since each hamburger costs $7.50 and Alang must buy a minimum of 18 hamburgers and drinks altogether, we subtract 18 from the maximum number of hamburgers Alang can buy.