Question 1119862
Bill and Mary are selling wrapping paper for a school fundraiser. Customers can buy rolls of plain wrapping paper and rolls of holiday wrapping paper. Bill sold 4 rolls of plain wrapping paper and 2 rolls of holiday wrapping paper for a total of $86. Mary sold 12 rolls of plain wrapping paper and 5 rolls of holiday wrapping paper for a total of $243. What is the cost each
of one roll of plain wrapping paper and one roll of holiday wrapping paper? 


x = cost of 1 roll of plain.
y = cost of 1 roll of hoiday.


equations are:


4x + 2y = 86 for bill.
12x + 5y = 243 for mary.


multiply both sides of the first eqution by 3 and leave the second equation as is to get:


12x + 6y = 258 for bill.
12x + 5y = 243 for mary


subtract the second equation from the first to get:
y = 258 - 243 = 15.


replace y with 15 in either of the original equations to solve for x.


i did:


4x + 2y = 86 for bill becomes 4x + 30 = 86 which becomes 4x = 56 which becomes x = 14.


you have x = 14 and y = 15.


replace x and y in both your original equations to confirm the solution is corre4ct.


4x + 2y = 86 for bill becomes 4*14 + 2*15 = 86 which becomes 56 + 30 = 86 which becomes 86 = 86 which is true.


12x + 5y = 243 for mary becomes 12*14 + 5*15 = 243 which becomes 168 + 75 = 243 which becomes 243 = 243 which is true.


both original equations are true when x = 14 and y = 15, therefore that solution looks good.


not sure why it's throwing you.


it's correct.


x and y represent the cost of 1 roll of plain and 1 roll of holiday.