Ferris Company Has an Old Machine That Is Fully Depreciated

Ferris Company has an old machine that is fully depreciated but has a current salvage value of $5,000.The company wants to purchase a new machine that would cost $60,000 and have a five-year useful life and zero salvage value.Expected changes in annual revenues and expenses if the new machine is purchased are:
$\begin{array}{|l|r|r|}\hline \text { Increased revenues } & \$ 20,000 & \$ 63,000 \\\hline \text { Increased expenses: } & 9,000 & \\\hline \text { Salary of additional operator } & & \\\hline \text { Supplies } & & \\\hline \text { Depreciation } 12,000 & & \\\hline \text { Maintenance } & \underline{4,000} & \mathbf{4 5 , 0 0 0} \\\hline\end{array}$
$$\begin{array} { | l | l | l | } \hline \text { Increased net income } & & \$ 18,000 \\\hline\end{array}$$
(Ignore income taxes in this problem.)
Required:
a)What is the payback period on the new equipment?
b)What is the simple rate of return on the new equipment?