What we can do is calculating what one bag cost. If we know that 5 cost 27.50 dollars, to know how much does one cost we only divide:
27.50/5 = 5.50 dollars
Now, we know how much does one bag cost, so we multiply it by three:
5.50 * 3 = 16.50
Now, we know 3 bags cost 16.5 dollars
if u need it to be negative.
they can both be solutions depends on the equation
what is the equation? ?