The average cost when producing x items is found by dividing the cost function, c(x), by the number of items, x.
when is the average cost less than 100, given the cost function is c(x) = 20x + 160?

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.