A computer engineering firm is considering three different systems $($System A$,$ System B$,$ and System C$).$

Given the following table cash flow showing cost and benefits of the four design options, answer the

following questions. Interest rate is $10\%$ :

Table Cash Flow $($S$)$

Present worth of system $($A$)$ is closest to:

b$.$ $$2,830$

$=-20,000+2,000(0\mathrm{.}9091)+2,300(0\mathrm{.}8264)+2,645(0\mathrm{.}7513)+3,042(0\mathrm{.}6830)+3,498(0\mathrm{.}6209)+4,023(0\mathrm{.}5645)+4,626(0\mathrm{.}5132)+5,320(0\mathrm{.}4665)+6,118(0\mathrm{.}4241)+7,036(0\mathrm{.}3855)$

c$.-$$$2,39C$

$=2,389\mathrm{.}5512$

d$.-$$$2,830$

Future worth $($end of year $10)$ of system $($B$)$ is closest to:

a$.$ $$7,896$

b$.$ $$6,636$

d$.$ $$4,970$

$=-8,000(2\mathrm{.}594)-10,000(2\mathrm{.}358)+2,000(2\mathrm{.}144)+2,500(1\mathrm{.}949)+3,000(1\mathrm{.}772)+3,500(1\mathrm{.}611)+4,000(1\mathrm{.}464)+4,500(1\mathrm{.}331)+5,000(1\mathrm{.}210)+5,500(1\mathrm{.}100)+6,000$

$=5,728\mathrm{.}500$

Internal rate of return $($IRR$)$ of system $($C$)$ is closest to:

a$.7\mathrm{.}96\%$

b$.9\mathrm{.}76\%$

c$.5\mathrm{.}4\%$

d$.-3\mathrm{.}48\%$

The best system from economic prospective is:

a$.$ System A

b$.$ System B

c$.$ System C

d$.$ Do$-$Nothing