Advertisements
Advertisements
Question
Evaluate `(n!)/((n-r)!)` when n = 6, r = 2
Advertisements
Solution
when n = 6, r = 2 `(n!)/((n-r)!) = (6!)/((6 - 2)!) = (6!)/(4!) = (6 xx 5 xx 4!)/(4!) = 30`
APPEARS IN
RELATED QUESTIONS
Is 3! + 4! = 7!?
How many words, with or without meaning, can be formed using all the letters of the word EQUATION, using each letter exactly once?
In how many ways can the letters of the word PERMUTATIONS be arranged if the vowels are all together.
Which of the following are true:
(2 +3)! = 2! + 3!
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 natural numbers not exceeding 4321 can be formed with the digits 1, 2, 3 and 4, if the digits can repeat?
If three six faced die each marked with numbers 1 to 6 on six faces, are thrown find the total number of possible outcomes ?
How many 5-digit telephone numbers can be constructed using the digits 0 to 9. If each number starts with 67 and no digit appears more than once?
In how many ways can 5 different balls be distributed among three boxes?
There are 10 lamps in a hall. Each one of them can be switched on independently. Find the number of ways in which the hall can be illuminated ?
Evaluate each of the following:
In how many ways 4 women draw water from 4 taps, if no tap remains unused?
Write the total number of possible outcomes in a throw of 3 dice in which at least one of the dice shows an even number.
Write the number of all possible words that can be formed using the letters of the word 'MATHEMATICS'.
The number of five-digit telephone numbers having at least one of their digits repeated is
The number of words from the letters of the word 'BHARAT' in which B and H will never come together, is
The number of arrangements of the letters of the word BHARAT taking 3 at a time is
English alphabet has 11 symmetric letters that appear same when looked at in a mirror. These letters are A, H, I, M, O, T, U, V, W, X and Y. How many symmetric three letters passwords can be formed using these letters?
Find x if `1/(6!) + 1/(7!) = x/(8!)`
How many numbers lesser than 1000 can be formed using the digits 5, 6, 7, 8, and 9 if no digit is repeated?
If nP4 = 12(nP2), find n.
In how many ways 5 boys and 3 girls can be seated in a row, so that no two girls are together?
How many 6-digit telephone numbers can be constructed with the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 if each numbers starts with 35 and no digit appear more than once?
Find the number of arrangements that can be made out of the letters of the word “ASSASSINATION”.
Find the rank of the word ‘CHAT’ in the dictionary.
The number of permutation of n different things taken r at a time, when the repetition is allowed is:
Determine the number of permutations of the letters of the word SIMPLE if all are taken at a time?
A test consists of 10 multiple choice questions. In how many ways can the test be answered if the first four questions have three choices and the remaining have five choices?
8 women and 6 men are standing in a line. How many arrangements are possible if any individual can stand in any position?
8 women and 6 men are standing in a line. In how many arrangements will all 6 men be standing next to one another?
8 women and 6 men are standing in a line. In how many arrangements will no two men be standing next to one another?
How many ways can the product a2 b3 c4 be expressed without exponents?
How many strings are there using the letters of the word INTERMEDIATE, if all the vowels are together
Choose the correct alternative:
The product of r consecutive positive integers is divisible b
The number of permutations of n different objects, taken r at a line, when repetitions are allowed, is ______.
If 1P1 + 2. 2p2 + 3. 3p3 + ....... 15. 15P15 = qPr – s, 0 ≤ s ≤ 1, then q+sCr–s is equal to ______.
If m+nP2 = 90 and m–nP2 = 30, then (m, n) is given by ______.
