Question $3\mathrm{.}4(15$pts$)$ Consider the following two mutually exclusive projects:

a$)$ What assumption$($s$)$ do you need in order to compare a set of mutually exclusive service projects with unequal service lives?

b$)$ With the assumption$($s$)$ defined in part $($a$)$ and using $10\%,$ determine which project should be selected.

c$)$ If your analysis period $($ study period$)$ is just $4$ years, what would be the salvage value of project $A2$ at the end of year $4$ to make the two alternatives economically indifferent?