Question

Kristin and Julio are selling cookie dough for a school fundraiser. Customers can buy packages of sugar cookie dough and
packages of gingerbread cookie dough. Kristin sold 9 packages of sugar cookie dough and 9 packages of gingerbread cookie
dough for a total of $162. Julio sold 13 packages of sugar cookie dough and 8 packages of gingerbread cookie dough for a
total of $169. What is the cost each of one package of sugar cookie dough and one package of gingerbread cookie dough?
A packag&of sugar cookie dough: $13, package of gingerbread cookie dough: $5
B. package of sugar cookie dough: $5, package of gingerbread cookie dough: $13
C. package of sugar cookie dough: $10, package of gingerbread cookie dough: $8
D. package of sugar cookie dough: $5, package of gingerbread cookie dough: $20

Answer 1

Answer: B

Explanation: Form 2 simultaneous equations
9s+9g=162 for Kristin (equation 1)
13s+8g=169 for Julio (equation 2)
If you get the coefficients for g to the same number you get
72s+72g=1296 (equation 1)
117s+72g=1521(equation 2)
You can then take equation 2 away from equation 1 leaving you with
45s=225
s=5
Then sub s=5 into the original equation
9s+9g=162
9x5+9g=162
45+9g=162
9g=117
g=13
Therefore s=$5 and g=$13