Question

For a certain manufacturer only 4/5 of the items produced are not defective if 2000 items are made in a month how many are not defective

Answer 1

Given:
4/5 of the items produced are not defective
2,000 items are produced in a month

Not defective:
2,000 * 4/5 = (2,000 * 4) / 5 = 8,000 / 5 = 1,600 

defective:
2,000 - 1,600 = 400

Out of the 2,000 items made in a month, only 1,600 items are not defective. The remaining 400 items are defective.