Answer: There are 2 dozens of peanut butter cookies, 4 dozens of sugar cookies and 5 dozens of chocolate chip cookies.
Explanation:
Since we have given that
Susan made chocolate chip cookies, peanut butter cookies and sugar cookies to sell at the bake sale.
Let number of chocolate chip cookies be c
Let the number of peanut butter cookies be p
Let the number of sugar cookies be s
Total number of cookies = 11 dozen
Our equation will be

According to question, we have that she made twice as many sugar cookies as peanut butter cookies,
So,

And she one dozen more of chocolate chip cookies than sugar cookies,

So, we have

So,

So, there are 2 dozens of peanut butter cookies, 4 dozens of sugar cookies and 5 dozens of chocolate chip cookies.