Question

The school is having a bake sale and the pep squad is selling cookies. On one ticket they sold two chocolate chip cookies and five oatmeal cookies for $23. On another ticket they sold three chocolate chip cookies and three oatmeal cookies for $21.

Which system of equations below can be used to determine the price of a chocolate chip cookie and the price of an oatmeal cookie?

Let x represent the cost of a chocolate chip cookie, and let y represent the cost of an oatmeal cookie.
A.
2x + 3y = 23
5x + 3y = 21

B.
2x + 3x = 20
5y + 3y = 24

C.
5x + 8y = 44
5x - 8y = 44

D.
2x + 5y = 23
3x + 3y = 21

Answer 1

`\begin{aligned}\textsf{D.}\quad 2x + 5y &= 23\\3x + 3y &= 21\end{aligned}`

Explanation:

Definition of variables:

• Let x represent the cost of a chocolate chip cookie
• Let y represent the cost of an oatmeal cookie.

Given information:

• 2 chocolate chip cookies and 5 oatmeal cookies = $23.
• 3 chocolate chip cookies and 3 oatmeal cookies = $21.

Therefore, the system of equations that can be used to determine the price of a chocolate chip cookie and the price of an oatmeal cookie is:

`\large\boxed{\begin{aligned}2x + 5y &= 23\\3x + 3y&= 21\end{aligned}}`