Hello!
To find which package would be most affordable, we can substitute 12 into both given packages to find which one would be the most cheap.
Package A: C = 7p + 5, C = total cost, p = number of people.
C = 7(12) + 5
C = 84 + 5
C = 89
If she chooses package A, it would cost 89 dollars to invite 12 people.
Package B: To find the equation for this package, we can find the common difference in the number of people.
19.00 - 12.50 = 6.5 and 25.50 - 29.00 = 6.5
Therefore, the equation for this package is C = 6.5p, C = total cost, p = number of people.
C = 6.5(12)
C= 78
If she chooses package B, it would cost her 78 dollars to invite 12 people.
Therefore, if your friend wants to invite 12 people to her birthday, she would go with Package B, because it is more cost-effective than Package A.