Write a system of equations to represent this situation. Then solve

Question

The seniors are having a bake sale. Cookies are $1 each and cupcakes are $3 each. Connie spends $15 for 7 items. How many of each type goodie did she buy?

Answer 1

The system of equations are: (Let x be the number of cookies she bought and y be the number of cupcakes she bought.)

x + 3y = 15 [ 1.x = the rate of cookie times the number of cookie; 3.y = the rate of cupcakes time the number of cupcakes; The sum of twos costs is $15.]

x + y = 7 [she bought 7 items total so, the sum of the number of two items is 7]

By solving these two equations, she bought 3 cookies and 4 cupcakes.

Answer 2

First you need to think of writing two equations. One equations will be the total number of items she bought, which would be x + y = 7 (with x being cookies and y being cupcakes). The other equation would involve the total cost of what she bought, so that would be 1x + 3y = 15 (since it cost $1 for a cookie and $3 for a cupcake. Then you have to solve it by graphing, substitution or elimination.