The credit terms should be changed to $\frac{4\mathrm{.}5}{10}$ net $60$ days. This is expected to increase credit sales to $55000$ units,

reduce the debtors collection period to $36\mathrm{.}50$ days, lower bad debts to $4\%$ of credit sales and increase the percentage of

the credit sales to which the discount applies to $70\%.$ What is the required rate of return on equal$-$risk investments is $18\%?$