67 guests
Explanation / Steps:
Since the budget is of $2,800.00, from it we need to remove first the renting charge (since this charge doesn't deppend on the amount of guests) :
$2,800.00 - $95.00 = $2,705
Then to find the amount of guest we'll divide this amount by the $40 fee for food and drinks per guests:
$2,705 / $40 = 67.625 guests
Since the number of guest cannot be a decimal number and you can't add to this number, you need to truncate it at the unity = 67 guests