JEE Main2012MathematicsProbabilityActual
If six students, including two particular students A and B , stand in a row, then the probability that A and B are separated with one student in between them is
Options
- A8 15
- B4 15
- C2 15
- D1 15
Correct answer
B. 4 15
Step-by-step solution
Consider a group of three students A, B and an other student in between A and B . Choice for a student between A and B is 4. A and B can interchange their places in the group in 2 ways. Now the group of three students (student A , student B and a student in between A and B ) and the remaining 3 students can be stand in a row in 4 ! ways. Hence total number of ways to stand in a row such that A and B are separated with one student in between them =4 2 4 ! Now total number of ways to stand 6 student stand in a row wi