Question

Describe permutation and combination formula

Answer 1

Permutation is defined as arrangement of r things that can be done out of total n things. This is denoted by nPr which is equal to n!/(n-r)!
Combination formula
Combination is defined as selection of r things that can be done out of total n things. This is denoted by nCr which is equal to n!/r!(n-r)!
As per the Fundamental Principle of Counting, if a particular thing can be done in m ways and another thing can be done in n ways, then either one of the two can be done in m + n ways and both of them can be done in m × n ways.