$6.$ A maintenance manager has four objectives to optimize to the selection his maintenance strategy. He has four objectives or criteria for selection. The objectives are cost, reliability, performance, and down time. The strategies to select from are the following four: run to failure $($RF$),$ time$-$based preventive $($TP$),$ condition based $($CB$)$ and combined time and condition based. CTBC$.$ He gathered his staff and obtained the following matrix that shows the pairwise comparisons among the objectives.