沃顿商学院《运营管理概论》题目求教 -不良品被转移到发运部的概率有多大？

有一条50道工序的生产线，每道工序产生质量缺陷的可能性是1%，其中任何一道工序产生缺陷都会导致最终产品的不良；生产线尾部有2个独立工作的质检员，每人捉到不良品的可能性是90%，抓到就报废，认为合格就转到发运部。

问题1：该生产线产生不良品的概率是多大？（不管是否有不良品是否被抓到没有）- 这道题答案很简单，0.394994

问题2：不良品被转移到发运部的概率有多大？- 这道题，我提交的答案是0.061286，但结果是错的

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?