文艺到mock题，2021年上午的Monmouth Case Scenario 2第二问 “Based on the data in exhibit 1, the expected price return on the BBB-rated bonds in River's porfolio over his horizon attributable to ratings migration is closest to"
答案的最后一步加总计算我算了好多次都是-0.573%，不知道怎么算出来正确答案
