An investment has an installed cost of $$531,800.$ The cash flows over the four$-$year life of the investment are projected to be $$217,850,$ $$234,450,$ $$201,110,$ and $$149,820,$ respectively. if the discount rate is zero what is the NPV$.$ if the discount rate is infinit, what is the NPV$?$ at what disciunt rate is the NPV just equal to zEro? Solve this question without financial calculator?