Answer:
9 sugar cookies
Explanation:
Let the number of sugar cookies be x.
If the number of oatmeal cookies was six more than the number of sugar cookies, then oatmeal cookies can be represented by x + 6.
So, we know that Samuel ate half of the oatmeal cookies and 2/3 of the sugar cookies, for a total of 18 cookies. Let's represent this with an equation.
x + x + 6 = 18
2x + 6 = 18
2x = 12
x = 6
So x represents 6. Recall that he ate 2/3 of the sugar cookies, so 2 parts of sugar cookies is 6.
Therefore, we can do this:
(3/2) x 6 = 9 cookies
This is essentially saying, "I want to find 3 parts if 2 parts is 6 cookies."
He ate 9 sugar cookies.