A project has the following after$-$tax total $($or net$)$ cash flows.

$\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$

Year After$-$tax total $($or net$)$ cash flow$\_$

$1$ $$100,000$

$2120,000$

$3150,000$

$4200,000$

$\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$

The required rate of return on the project is $15$ percent. The initial investment $($or initial cost or initial outlay$)$ of the project is $$320,000.$

a$)$ Find the $($regular$)$ payback period of the project.

b$)$ Compute the discounted payback period of the project.