An investment has an installed cost of $$787,350.$ The cash flows over the four$-$year life of the investment are projected to be $$312,615,$ $$304,172,$ $$245,367,$ and $$229,431.$

a$.$ If the discount rate is zero, what is the NPV$?($Do not round intermediate calculations and round your answer to the nearest whole number, e$.$g$.,32.)$

b$.$ If the discount rate is infinite, what is the NPV$?($A negative answer should be indicated by a minus sign. Do not round intermediate calculations and round your answer to the nearest whole number, e$.$g$.,32.)$

c$.$ At what discount rate is the NPV equal to zero? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$