不是应该用expected return 来折现吗？解题中，为啥用了90%概率和85%概率对应的return？

NO.PZ2018110601000039 问题如下 Remington anMontgomery scuss Isabelle Sebastian. ring a recentconversation, Sebastian, a long-term client with a $2,900,000 investmentportfolio, reminRemington thshe will soon turn age 65 anwants toupte her investment goals follows:Go1: Over the next 20 years, she nee to maintainher living expentures, whiare currently $120,000 per ye(90% probabilityof success). Inflation is expecteto average 2.5% annually over the timehorizon, anwithawals take plathe beginning of the year, startingimmeately.Go2: In 10 years, she wants to nate $1,500,000 in nomintermsto a charitable fountion (85% probability of success).Exhibit 2 provisthe tails of the two sub-portfolios, inclung Sebastian’s allocation to thesub-portfolios anthe probabilities ththey will exceethe expecteminimumreturn.Exhibit 2 Investment Sub-Portfolios Minimum ExpecteReturnfor Success Rate Assume 0% correlation betweenthe time horizon portfolios.UsingExhibit 2, whiof the sub-portfolio allocations is most likely to meet bothof Sebastian’s goals? A.The current sub-portfolio allocation. A 43% allocation to sub-portfolio ana 57%allocation to sub-portfolio CZ. C.A 37%allocation to sub-portfolio ana 63% allocation to sub-portfolio CZ. C is correct.Go1 关键词90% probability of success，20 years。通过查表，选择portfolio，minimum expectereturn=5.7%。5.7%是名义利率，当前每年生活费$120,000会以2.5%的通货膨胀率增长，所以实际利率=(1+5.7%)/(1+2.5%)-1=3.12%.（近似法5.7%-2.5%=3.2%也可行，计算结果影响不大。）计算CZ的PV由于第一笔现金流发生在0时刻，所以要使用计算器BGN模式输入N=20, I/Y=3.12, FV=0,PMT=120,000，得出PV=1,820,738.Go2 关键词85% probability of success，10 years。通过查表，选择portfolio，minimum expectereturn=3.6%。计算BY的PV将期末的$1.5m折到0时刻，得出PV=1,500,000/1.03610=1,053,158。CZ占比1,820,738 / 2,900,000=62.78%BY占比1,053,158 / 2,900,000=36.32%所以最接近 Go2 用先付年金还是后附年金？ why？ N=10, FV=1,500,000, PMT=0, I/Y=3.6

NO.PZ2018110601000039 问题如下 Remington anMontgomery scuss Isabelle Sebastian. ring a recentconversation, Sebastian, a long-term client with a $2,900,000 investmentportfolio, reminRemington thshe will soon turn age 65 anwants toupte her investment goals follows:Go1: Over the next 20 years, she nee to maintainher living expentures, whiare currently $120,000 per ye(90% probabilityof success). Inflation is expecteto average 2.5% annually over the timehorizon, anwithawals take plathe beginning of the year, startingimmeately.Go2: In 10 years, she wants to nate $1,500,000 in nomintermsto a charitable fountion (85% probability of success).Exhibit 2 provisthe tails of the two sub-portfolios, inclung Sebastian’s allocation to thesub-portfolios anthe probabilities ththey will exceethe expecteminimumreturn.Exhibit 2 Investment Sub-Portfolios Minimum ExpecteReturnfor Success Rate Assume 0% correlation betweenthe time horizon portfolios.UsingExhibit 2, whiof the sub-portfolio allocations is most likely to meet bothof Sebastian’s goals? A.The current sub-portfolio allocation. A 43% allocation to sub-portfolio ana 57%allocation to sub-portfolio CZ. C.A 37%allocation to sub-portfolio ana 63% allocation to sub-portfolio CZ. C is correct.Go1 关键词90% probability of success，20 years。通过查表，选择portfolio，minimum expectereturn=5.7%。5.7%是名义利率，当前每年生活费$120,000会以2.5%的通货膨胀率增长，所以实际利率=(1+5.7%)/(1+2.5%)-1=3.12%.（近似法5.7%-2.5%=3.2%也可行，计算结果影响不大。）计算CZ的PV由于第一笔现金流发生在0时刻，所以要使用计算器BGN模式输入N=20, I/Y=3.12, FV=0,PMT=120,000，得出PV=1,820,738.Go2 关键词85% probability of success，10 years。通过查表，选择portfolio，minimum expectereturn=3.6%。计算BY的PV将期末的$1.5m折到0时刻，得出PV=1,500,000/1.03610=1,053,158。CZ占比1,820,738 / 2,900,000=62.78%BY占比1,053,158 / 2,900,000=36.32%所以最接近 请问这题考的是什么知识点啊。。。。。。重要程度如何

NO.PZ2018110601000039 问题如下 Remington anMontgomery scuss Isabelle Sebastian. ring a recentconversation, Sebastian, a long-term client with a $2,900,000 investmentportfolio, reminRemington thshe will soon turn age 65 anwants toupte her investment goals follows:Go1: Over the next 20 years, she nee to maintainher living expentures, whiare currently $120,000 per ye(90% probabilityof success). Inflation is expecteto average 2.5% annually over the timehorizon, anwithawals take plathe beginning of the year, startingimmeately.Go2: In 10 years, she wants to nate $1,500,000 in nomintermsto a charitable fountion (85% probability of success).Exhibit 2 provisthe tails of the two sub-portfolios, inclung Sebastian’s allocation to thesub-portfolios anthe probabilities ththey will exceethe expecteminimumreturn.Exhibit 2 Investment Sub-Portfolios Minimum ExpecteReturnfor Success Rate Assume 0% correlation betweenthe time horizon portfolios.UsingExhibit 2, whiof the sub-portfolio allocations is most likely to meet bothof Sebastian’s goals? A.The current sub-portfolio allocation. A 43% allocation to sub-portfolio ana 57%allocation to sub-portfolio CZ. C.A 37%allocation to sub-portfolio ana 63% allocation to sub-portfolio CZ. C is correct.Go1 关键词90% probability of success，20 years。通过查表，选择portfolio，minimum expectereturn=5.7%。5.7%是名义利率，当前每年生活费$120,000会以2.5%的通货膨胀率增长，所以实际利率=(1+5.7%)/(1+2.5%)-1=3.12%.（近似法5.7%-2.5%=3.2%也可行，计算结果影响不大。）计算CZ的PV由于第一笔现金流发生在0时刻，所以要使用计算器BGN模式输入N=20, I/Y=3.12, FV=0,PMT=120,000，得出PV=1,820,738.Go2 关键词85% probability of success，10 years。通过查表，选择portfolio，minimum expectereturn=3.6%。计算BY的PV将期末的$1.5m折到0时刻，得出PV=1,500,000/1.03610=1,053,158。CZ占比1,820,738 / 2,900,000=62.78%BY占比1,053,158 / 2,900,000=36.32%所以最接近 老师好 什么时候用实际利率， 什么时候用nominrate? 有没有规律? go1 为啥要用reinterest rate?谢谢。

NO.PZ2018110601000039 问题如下 Remington anMontgomery scuss Isabelle Sebastian. ring a recentconversation, Sebastian, a long-term client with a $2,900,000 investmentportfolio, reminRemington thshe will soon turn age 65 anwants toupte her investment goals follows:Go1: Over the next 20 years, she nee to maintainher living expentures, whiare currently $120,000 per ye(90% probabilityof success). Inflation is expecteto average 2.5% annually over the timehorizon, anwithawals take plathe beginning of the year, startingimmeately.Go2: In 10 years, she wants to nate $1,500,000 in nomintermsto a charitable fountion (85% probability of success).Exhibit 2 provisthe tails of the two sub-portfolios, inclung Sebastian’s allocation to thesub-portfolios anthe probabilities ththey will exceethe expecteminimumreturn.Exhibit 2 Investment Sub-Portfolios Minimum ExpecteReturnfor Success Rate Assume 0% correlation betweenthe time horizon portfolios.UsingExhibit 2, whiof the sub-portfolio allocations is most likely to meet bothof Sebastian’s goals? A.The current sub-portfolio allocation. A 43% allocation to sub-portfolio ana 57%allocation to sub-portfolio CZ. C.A 37%allocation to sub-portfolio ana 63% allocation to sub-portfolio CZ. C is correct.Go1 关键词90% probability of success，20 years。通过查表，选择portfolio，minimum expectereturn=5.7%。5.7%是名义利率，当前每年生活费$120,000会以2.5%的通货膨胀率增长，所以实际利率=(1+5.7%)/(1+2.5%)-1=3.12%.（近似法5.7%-2.5%=3.2%也可行，计算结果影响不大。）计算CZ的PV由于第一笔现金流发生在0时刻，所以要使用计算器BGN模式输入N=20, I/Y=3.12, FV=0,PMT=120,000，得出PV=1,820,738.Go2 关键词85% probability of success，10 years。通过查表，选择portfolio，minimum expectereturn=3.6%。计算BY的PV将期末的$1.5m折到0时刻，得出PV=1,500,000/1.03610=1,053,158。CZ占比1,820,738 / 2,900,000=62.78%BY占比1,053,158 / 2,900,000=36.32%所以最接近 这道题20年的收益率没有明白，20年的收益率平均大于10年，也就是说这个收益率是作为一个投资期为20年的asset去计算的。但是这道题从刚开始就要去每年取钱，也就是说这道题的第一个资产是逐年去取，取到20年正好取完。这类资产类型归为长期资产适用一个比10年期还要高的折现率是否不太合理了？