show all detailed calculations and working arriving at the answer.

$8-4.$ In Problem $8-3,$ assume that receipts will be $$31,500$ in the first year

and that they will decline by $$300$ each year to $$24,300$ in the $25$ th year,

Assume that disbursements for everything except income taxes will be $$12,660$

in the first year and will increase by $$200$ a year to $$17,460$ in the $25$ th year.

Assume that disbursements for income taxes will be $$7,420$ in the first year and

will decrease by $$250$ a year to $$1,420$ in the $25$ th year. Compute the pros$-$

pective after$-$tax rate of return.

$(Ans.=6\mathrm{.}2\%.)$