想请教一道书上的例题，谢谢老师~

NO.PZ2018091901000056问题如下investor is consiring aing three new securities to her internationally focusefixeincome portfolio. She consirs the following non-callable securities:1-yegovernment bon 10-yegovernment bon0-yeBratecorporate bonhe plans to invest equally in all three securities being analyzeor will invest in none of them this time. She will only make the aeinvestment proviththe expectespreapremium of the equally weighteinvestment is least 1.5 percent (150bp) over the 1-yegovernment bon She hgatherethe following information:Using only the information given, calculate the expectetotrisk premium of the three securities antermine the investor’s probable course of action.A.invest equally in all three securities B. not invest equally in all three securities C.uncertain B is correct.The average spreaover 1-yegovernment bon issue is [0 + 1 + (1 + 0.75 + 0.55)] = 3.3%/3= 1.1%. the 1.1% isless th1.5%, the investor will not make the investment.解析1-yegovernment bon有任何风险溢价，所以它的SPREA是0。相比较于1-yegovernmentbon10-yegovernment bonSPREA1%。相比较于1-yegovernmentbon10-yecorporate bonSPREA1% + 0.75% + 0.55%。又因为这三类债券投资权重相等，所以直接求算数平均就可以求得投资的SPREA即[0 + 1 + (1 + 0.75+ 0.55)] = 3.3%/3 = 1.1%.又因为这个SPREA于投资者想要的回报率1.5%，所以投资者不会去做投资。 请问老师解题为什么不是[3.8+ 4.8 + (4.8+ 0.75 + 0.55)] = 14.7%/3 = 4.9%.Expectesprea4.9%-3.8%=1.1%又因为这个SPREA于投资者想要的回报率1.5%，所以投资者不会去做投资。

NO.PZ2018091901000056 问题如下 investor is consiring aing three new securities to her internationally focusefixeincome portfolio. She consirs the following non-callable securities:1-yegovernment bon 10-yegovernment bon0-yeBratecorporate bonhe plans to invest equally in all three securities being analyzeor will invest in none of them this time. She will only make the aeinvestment proviththe expectespreapremium of the equally weighteinvestment is least 1.5 percent (150bp) over the 1-yegovernment bon She hgatherethe following information:Using only the information given, calculate the expectetotrisk premium of the three securities antermine the investor’s probable course of action. A.invest equally in all three securities B. not invest equally in all three securities C.uncertain B is correct.The average spreaover 1-yegovernment bon issue is [0 + 1 + (1 + 0.75 + 0.55)] = 3.3%/3= 1.1%. the 1.1% isless th1.5%, the investor will not make the investment.解析1-yegovernment bon有任何风险溢价，所以它的SPREA是0。相比较于1-yegovernmentbon10-yegovernment bonSPREA1%。相比较于1-yegovernmentbon10-yecorporate bonSPREA1% + 0.75% + 0.55%。又因为这三类债券投资权重相等，所以直接求算数平均就可以求得投资的SPREA即[0 + 1 + (1 + 0.75+ 0.55)] = 3.3%/3 = 1.1%.又因为这个SPREA于投资者想要的回报率1.5%，所以投资者不会去做投资。 题目中说---She will only make the aeinvestment proviththe expectespreapremium of the equally weighteinvestment is least 1.5 percent (150bp) over the 1-yegovernment bon----- 在实际中，难道不是要求sprea小越好吗？

NO.PZ2018091901000056问题如下 investor is consiring aing three new securities to her internationally focusefixeincome portfolio. She consirs the following non-callable securities:1-yegovernment bon 10-yegovernment bon0-yeBratecorporate bonhe plans to invest equally in all three securities being analyzeor will invest in none of them this time. She will only make the aeinvestment proviththe expectespreapremium of the equally weighteinvestment is least 1.5 percent (150bp) over the 1-yegovernment bon She hgatherethe following information:Using only the information given, calculate the expectetotrisk premium of the three securities antermine the investor’s probable course of action.A.invest equally in all three securities B. not invest equally in all three securities C.uncertain B is correct.The average spreaover 1-yegovernment bon issue is [0 + 1 + (1 + 0.75 + 0.55)] = 3.3%/3= 1.1%. the 1.1% isless th1.5%, the investor will not make the investment.解析1-yegovernment bon有任何风险溢价，所以它的SPREA是0。相比较于1-yegovernmentbon10-yegovernment bonSPREA1%。相比较于1-yegovernmentbon10-yecorporate bonSPREA1% + 0.75% + 0.55%。又因为这三类债券投资权重相等，所以直接求算数平均就可以求得投资的SPREA即[0 + 1 + (1 + 0.75+ 0.55)] = 3.3%/3 = 1.1%.又因为这个SPREA于投资者想要的回报率1.5%，所以投资者不会去做投资。 Rf中有提到inflation rate～这个Rf3.8%与inflation rate2.6%有啥关系？

NO.PZ2018091901000056问题如下investor is consiring aing three new securities to her internationally focusefixeincome portfolio. She consirs the following non-callable securities:1-yegovernment bon 10-yegovernment bon0-yeBratecorporate bonhe plans to invest equally in all three securities being analyzeor will invest in none of them this time. She will only make the aeinvestment proviththe expectespreapremium of the equally weighteinvestment is least 1.5 percent (150bp) over the 1-yegovernment bon She hgatherethe following information:Using only the information given, calculate the expectetotrisk premium of the three securities antermine the investor’s probable course of action. A.invest equally in all three securities B. not invest equally in all three securities C.uncertain B is correct.The average spreaover 1-yegovernment bon issue is [0 + 1 + (1 + 0.75 + 0.55)] = 3.3%/3= 1.1%. the 1.1% isless th1.5%, the investor will not make the investment.解析1-yegovernment bon有任何风险溢价，所以它的SPREA是0。相比较于1-yegovernmentbon10-yegovernment bonSPREA1%。相比较于1-yegovernmentbon10-yecorporate bonSPREA1% + 0.75% + 0.55%。又因为这三类债券投资权重相等，所以直接求算数平均就可以求得投资的SPREA即[0 + 1 + (1 + 0.75+ 0.55)] = 3.3%/3 = 1.1%.又因为这个SPREA于投资者想要的回报率1.5%，所以投资者不会去做投资。 She will only make the aeinvestment proviththe expectespreapremium of the equally weighteinvestment is 【least 1.5 percent (150bp) over the 1-yegovernment bon投资者要求的回报率是1年的国债收益率+1.5%=2.5%吧？为啥答案说是1.5%？