It has been decided that whole body scanning technology will be used for airport security purposes. Two types of devices are being

considered at a certain airport $($only one will be selected$)$: back scatter $($B$)$ and millimeter wave $($W$).$ The selected scanning equipment

is to be used for six years at which time better technology will be available. Thus, neither equipment type $(B$ or $W)$ will be considered

useful after the $6-$year period. The economic decision criterion at this airport is to meet or exceed a $15\%$ annual return on its

investment. Based on the data found in the table below which scanner should be selected? Use the PW method of analysis.