An investment project has annual cash inflows of $$3,300,$ $$4,200,$ $$5,400,$ and $$4,600,$ and a discount rate of $15$ percent.

a$.$ What is the discounted payback period for these cash flows if the initial cost is $$6,000?($Do not round intermediate calculations and round your answer to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

b$.$ What is the discounted payback period for these cash flows if the initial cost is $$8,100?($Do not round intermediate calculations and round your answer to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

c$.$ What is the discounted payback period for these cash flows if the initial cost is $$11,100?($Do not round intermediate calculations and round your answer to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$