AP EAMCET202022 Sep 2020Morning ShiftMathematicsPermutation and CombinationActual
Find the number of ways of arrangement 6 red balls and 6 black balls in a row such that no two black ball are together.
Options
- A6 ! 6 !
- B7 ! 6 !
- C2 6 ! 6 !
- D7 6 ! 6 !
Correct answer
D. 7 6 ! 6 !
Step-by-step solution
Number of ways to arrange 6 red balls are 6 !. Now, there are seven positions to place 6 black balls, such that no two black balls are together So, number of ways to arrange 6 black balls are ^7 P₆ . Therefore the required number of arrangements =6 ! ^7 P₆=6 ! 7 !=7 6 ! 6 !