I want the solution of both options a and b. Thanks.

A manufacturing company uses an acceptance scheme on items from a production line before they are shipped. The plan is a two-stage one. Boxes of 29 items are readied for shipment, and a sample of 3 items is tested for defectives. If any defectives are found, the entire box is sent back for 100% screening. If no defectives are found, the box is shipped. (a) What is the probability that a box containing 4 defectives will be shipped? (b) What is the probability that a box containing only 1 defective will be sent back for screening? (a) The probability that a box containing 4 defectives will be shipped is (Round to four decimal places as needed.)