Advertisements
Advertisements
Question
The number of permutation of n different things taken r at a time, when the repetition is allowed is ______.
Options
rn
nr
`(n!)/((n - r)!)`
`(n!)/((n + r)!)`
Advertisements
Solution
The number of permutation of n different things taken r at a time, when the repetition is allowed is nr.
Explanation:
The correct answer is nr because when repetition is allowed, each of the r positions can be filled by any one of the n different objects. Thus, the total number of possible permutations is n × n × ... × n = nr.
APPEARS IN
RELATED QUESTIONS
A customer forgets a four-digits code for an Automatic Teller Machine (ATM) in a bank. However, he remembers that this code consists of digits 3, 5, 6 and 9. Find the largest possible number of trials necessary to obtain the correct code.
How many numbers of four digits can be formed with the digits 1, 2, 3, 4, 5 if the digits can be repeated in the same number?
Write the number of all possible words that can be formed using the letters of the word 'MATHEMATICS'.
Write the number of ways in which 5 boys and 3 girls can be seated in a row so that each girl is between 2 boys ?
The product of r consecutive positive integers is divisible by
The number of different ways in which 8 persons can stand in a row so that between two particular persons A and B there are always two persons, is
How many five digits telephone numbers can be constructed using the digits 0 to 9 If each number starts with 67 with no digit appears more than once?
In how many ways 5 boys and 3 girls can be seated in a row, so that no two girls are together?
The possible outcomes when a coin is tossed five times:
Find the sum of all 4-digit numbers that can be formed using digits 0, 2, 5, 7, 8 without repetition?
