The interest rate for evaluating the project. Given: Project B has a cost of $50,000. Annual benefit is $9,000.

Concept used:
Write the formula to calculate the interest rate.
${\displaystyle P=A\times \left(\frac{{(1+i)}^n-1}{i{(1+i)}^n}\right)}$ .......(I)
Here, the project cost is P, annual benefit is A, the time period is n and interest rate is i.
Table giving the example risk adjusted MARR values in manufacturing.
$\begin{array}{|cc|}\hline \text{Rate \%}& \text{Applied To}\\ 6& \text{Equipment replacement}\\ 8& \text{New equipment}\\ 10& \text{New prouct in normal market}\\ 12& \text{New product in new product}\\ 16& \text{New product in new product}\\ 20& \text{New product in foreign market}\\ \hline\end{array}$
Calculation:
Substitute $50,000 for P $9,000 for A and 10 years for n in Equation (I).
${\displaystyle \mathrm{\$}50,000=\mathrm{\$}9,000\times \left(\frac{{(1+i)}^{10}-1}{i{(1+i)}^{10}}\right)}$
${\displaystyle i=12.4\mathrm{\%}}$
As ${\displaystyle 12.4\mathrm{\%}>8\mathrm{\%}}$.
The new product in the new market should be accepted as proposed.
Conclusion:
Interest rate for evaluating project B is ${\displaystyle 12.4\mathrm{\%}}$.
The new product in the new market should be accepted as proposed.