Answer:
a. Risk-free rate of return:
= Real rate of return + Inflation premium
= 3.2% + 5.1%
= 8.3%
b. Required return for investment A:
= Risk free rate of return + Risk premium
= 8.3% + 7.4%
= 15.7%
Required return for investment B
= 8.3% + 8.9%
= 17.2%