$9\mathrm{.}1.$a$.$ What is an opportunity cost rate?

$9\mathrm{.}1.$b$.$ How is this rate used in time value analysis?

$9\mathrm{.}1.$c$.$ Is this rate a single number that is used in all situations?

$9\mathrm{.}4.$ Would you rather have a savings account that pays $5$ percent compounded semiannually or one that pays $5$ percent compounded daily? Explain your answer.

$9\mathrm{.}8.$ What are three techniques for solving time value problems?

$9\mathrm{.}9$ Explain the concept of return on investments $($ROI$)$ and the two different approaches to measuring it$?$