沃頓商學院《運營管理概論》題目求教 -不良品被轉移到發運部的概率有多大？

有一條50道工序的生產線，每道工序產生質量缺陷的可能性是1%，其中任何一道工序產生缺陷都會導致最終產品的不良；生產線尾部有2個獨立工作的質檢員，每人捉到不良品的可能性是90%，抓到就報廢，認為合格就轉到發運部。

問題1：該生產線產生不良品的概率是多大？（不管是否有不良品是否被抓到沒有）- 這道題答案很簡單，0.394994

問題2：不良品被轉移到發運部的概率有多大？- 這道題，我提交的答案是0.061286，但結果是錯的

Consider an assemblyline with 50 steps that are carried out sequentially. Each of the 50 steps hasa defect probability of 1%. The final product produced on the assembly line isdefective if any one of the 50 steps made a defect.

At the end of theassembly line there are two operators independently inspecting the product.Each of them is recognizing a defective product with a 90% probability.Assuming that the product is not defective, it is moved to the shippingdepartment. Otherwise, the product is scrapped.

50SAL1. What is the probability that a defectiveproduct is produced (independent of the defect being found or not)?

50SAL2. What is the probability that a defective product is moved to theshipping department?