$($Copy machines $o+)$ Two copy machines are available. Both have useful lives of $5$ years. One machine can be either leased or purchased outright; the other must be purchased. Hence there are a total of three options: A$,$ B$,$ and C$.$ The details are shown in Table $2\mathrm{.}5.($The first year's maintenance is included in the initial cost. There are then four additional maintenance payments, occurring at the beginning of each year, followed by revenues from resale.$)$ The present values of the expenses of these three options using a $10\%$ interest rate are also indicated in the table. According to a present value analysis, the machine of least cost, as measured by the present value, should be selected; that is$,$ option B$.$

TABLE $2\mathrm{.}5$ COPY MACHINE OPTIONS

$\backslash$table$[[,$Option$],[,$A$,$B$,$C$],[$Initial outlay,$6,000,30,000,35,000],[$Yearly expense,$8,000,2,000,1,600],[$Resale value,$0,10,000,12,000],[$Present value $($@ $10\%),31,359,30,131,32,621]]$

Option $A$ is a lease; options $B$ and $C$ are purchases of two alternative machines. All have $5-$year lives.

It is not possible to compute the IRR for any of these alternatives, because all cash flows are negative $($except for the resale values$).$ However, it is possible to calculate the IRR on an incremental basis. Find the IRR corresponding to a change from A to B$.$ Is a change from $A$ to $B$ justified on the basis of the IRR?