Answer:
c + 3c - 6 = 166
Explanation:
Let c = number of chocolate chip cookies.
"The number of sugar cookies sold was 6 fewer than three times the number of chocolate chip cookies sold."
The number of sugar cookies sold is: 3c - 6
The total number of cookies sold is c + 3c - 6.
Last week, the bakery sold a total of 166 cookies.
c + 3c - 6 = 166