25 students
Pizza - $3
Sandwiches - $2
12 students x $3 Pizza = $36
25 students - 12 students = 13 students bought sandwiches
13 students x $2 sandwiches =
$26 spent on sandwiches.
I hope this helps!
Not quite sure sorry edit : Oh sorry I supposed to add this in the comment section
I hope this helps - it depends what you doing for it to be negative or nonnegative.. :)