Answer:
<h2>Santa ate one sugar cookie and 1 chocolate chip cookies.</h2>
Step-by-step explanation:
We know that
<h3>Santa ate the same number of sugar cookies and chocolate chip cookies.</h3>
If
represents sugar cookies, and
represents chocolate chip cookies.
This part of the problem is expressed as
Because Santa ate the same of each type.
<h3>Twice the number of sugar cookies he ate decreased by one equals the number of chocolate chip cookies.</h3>
Now, this part of the problem is expressed

Because twice of sugar cookies decreased by one is equals to chocolate chip cookies.
Replacing the first equation into the second one, we have

Now, replacing this value in the first equation, we have

Therefore, Santa ate one sugar cookie and 1 chocolate chip cookies.