Answer:
They sold 14 $25 certificates.
Explanation:
System of Equations. To work through this, we will need two equations.
x : number of $25 gift certificates
y : number of $50 gift certificates
The total number of gift certificiates is 20, so the equation we create is:
x + y = 20
They sold the certificates for a total of $650, so we can create the equation:
25x + 50y = 650
The 25 represents the cost for an x number of ceriticates, and the 50 represents the cost for the y number of certificates.
To solve a system of equations, we can use either substitution or elimination. Here, we will use substitution.
x + y = 20
x = 20 - y
25x + 50y = 650
25(20 - y) + 50y = 650
500 - 25y + 50y = 650
500 + 25y = 650
25y = 150
y = 6
Substitute y in for one of the previous equations
x + y = 20
x + 6 = 20
x = 14
They sold 14 $25 certificates and 6 $50 dollar certificates.