AP EAPCET 04-Jul-2022 Shift 1 Paper

Total number of things =n
Repetition of things is allowed and atmost r can be taken at a time.
The number of ways of taking 1 thing at a time =boldsymbol‌n
The number of ways of taking 2 things at a time =n2
The number of ways of taking 3 things at a time =n3.......
The number of ways of taking r things at a time =n′
Total number of permutations of n different things taken not more than r at a time i.e. number of permutations of taking 1,2,....r at a time.
‌=n+n2+n3+...+nr
‌=‌

n(nr−1)

n−1

‌‌[∵‌ sum of GP] ‌