First job can be filled in 5 ways by anyone of the five numbers. Out of the five, if one is selected for the first job, then second job can be filled by the remaining 4 members in 4 ways. Hence number of ways of filling the first and second jobs = 5 x 4 = 20
Quantitative Aptitude MCQ - Permutation And Combinations
5 jobs can be filled by 5 members in  5P5 ways.
 5P5 = 5 ! = 5 x 4 x 3 x 2 x 1Â
= 120 ways.
 5P5 = 5 ! = 5 x 4 x 3 x 2 x 1Â
= 120 ways.
There are four ways to go from A to B and three ways to go from B to C, Hence there are 4 / 3 = 12 ways to go from A to C by way of R
