When to use permutation/combination in a given question of permutation and combunation - Maths - Permutations and Combinations

Question

When to use permutation/combination in a given question of
permutation and combunation?

Rizwan Ansari · Accepted Answer

Permutation: Each of the arrangements which can be made by taking some or all of a number of things is called a permutation For example, if there are three objects x, y and z, then the permutations of these objects taking two at a time are xy, xz, yx, yz, zx and zy In permutation the order of arrangement is taken into account When the order is changed, a different permutation is obtained The notation of permutation is given by ${}^{n}{P_{r}} = Total number of permutations of n different things, taken r at a time$ Combination: Each of the different selections made by taking some or all objects irrespective of their arrangement is called combination For example, if there are three objects x, y and z, then the combinations of these objects taking two at a time are {x,y}, {y,z} and {z,x} In combination the order of arrangement is not taken into account ${}^{n}{C_{r}} = Total number of ways of selecting r objects from n different object s$ In simple language, â‡’ If the order does matter, it is permutation â‡’ If the order doesn't matter, it is combination

When to use permutation/combination in a given question of permutation and combunation?