Crystal bought b boxes of cookies to bring to a party. Each box contains 18 cookies. She decides to keep two boxes for herself. She brings 90 cookies to the party. Which equation can be used to find the number of b boxes Crystal bought?
Responses
A 2b − 18 = 90
B 18b − 2 = 90
C 18b − 36 = 90
D36 − 18b = 90
We know that Crystal bought b boxes of cookies and each box contains 18 cookies. So, the total number of cookies she bought is 18b.
She decides to keep two boxes for herself, which means she keeps 2 x 18 = 36 cookies for herself.
So, the number of cookies she brings to the party is 18b - 36.
Since it is given that she brings 90 cookies to the party, we can set up the equation 18b - 36 = 90.
Therefore, the correct equation is C) 18b - 36 = 90.