The operations you would use are multiplication and subrtraction
(the reason for this is because you need to find the cost for 30 people normally --1230 -- and then subtract the discount -- 330 -- to find the total cost)
In the mathematical sentence (also known as the equation) we'll let the variable 'c' equal the total cost for all 30 students.
This means c=12(30) -3(30)
To break it down you write it this way because you need to find the cost before the discount (1230), then subtract the discount (330) to get the total cost (c).
Next, you just need to solve;
c=12(30)-3(30)
c=360-90
c=270
This means that the total cost for all 30 students will be $270.
I hope this helps!!!
