JB Permutation & Combination

Question 1

nPr

Answer 1

n!/(n-r)!

Question 2

nCr

Answer 2

n!/[r! x (n-r)!]

Question 3

Order matters

Answer 3

Permutation

Question 4

Order doesn’t matter

Answer 4

Combination

Question 5

Arrangements

Answer 5

Permutation

Question 6

Grouping or selection

Answer 6

Combination

Question 7

Arrangement of n different objects in straight line

Answer 7

n!

Question 8

Arrangement of n different objects in a circle

Answer 8

(n-1)!

Question 9

Arrangements for Mississippi

Answer 9

11!/[4! x 4! x 2!]

Question 10

Number of arrangements when some objects are together
eg - [a v e] d f g : ave need to be together

Answer 10

Arrangement of all objects considering box as single object x arrangement inside box
= 4! x 3!