There is a group of 7 people and 4 chairs are available. You want to seat 4, then the order matters
First chair can be filled in 7 ways
Second chair can be filled in 6 ways
Third chair can be filled in 5 ways
Fourth chair can be filled in 4 ways
Total ways = 7 * 6 * 5 * 4
On the other hand, if you are making a team of 4 from a group of 7, order does not
matters. Its 7C4
A = First person can be chosen in 7 ways
B = Second person - 6 ways
C = Third person - 5 ways
D = Fourth person - 4 ways
But ABCD = BCDA = CDAB = DABA ..... etc
So you have duplicates. There will be 4! duplicates per selection
To make unique teams, you will have to divide by 4!
Hence no of ways = 7 * 6 * 5 * 4 / (4!) = 7C4
can someone pls explain this concept..?
what do we mean by order does matter and order does not matter...??
for eg..) if we need to know the seating arrangement for 4 persons from 7 chairs,,,we take order matters and if we need to make a team of 4 people from 7 people in a room we take order not matters....??
or is there a better method to identify when order matters and when order does not matters...??