In a factory for five jobs the members A, B, C, D, E are eligible.
In how many ways the first two jobs can be filled?
A. | 20 |
B. | 30 |
C. | 60 |
D. | 120 |
Option: A Explanation : 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 |
All jobs can be filled in hcw many ways?
A. | 20 |
B. | 40 |
C. | 60 |
D. | 120 |
Option: D Explanation :
5 jobs can be filled by 5 members in^{ 5}P_{5 }ways. |
If 6 identical coins are arranged in a row, then number of arrangements in which 4 are heads and 2 are tails are
A. | 4 |
B. | 6 |
C. | 12 |
D. | 15 |
Option: D Explanation : |
l'here are four bus lines between A and B; and three bus lines between Band C.
The number of ways a person can travel by bus from A to C by way of B will be
A. | 10 |
B. | 12 |
C. | 14 |
D. | 24 |
Option: B Explanation : 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 ofR |