Advertisements
Advertisements
प्रश्न
How many six-digit telephone numbers can be formed if the first two digits are 45 and no digit can appear more than once?
Advertisements
उत्तर
Let the telephone number be 45 abcd
| Number of ways to fill | |
| a | 8 |
| b | 7 |
| c | 6 |
| d | 5 |
Required number = 8P4 = 1680
APPEARS IN
संबंधित प्रश्न
Find r if `""^5P_r = 2^6 P_(r-1)`
In how many of the distinct permutations of the letters in MISSISSIPPI do the four I’s not come together?
In how many ways can the letters of the word PERMUTATIONS be arranged if the words start with P and end with S.
Find x in each of the following:
How many natural numbers less than 1000 can be formed from the digits 0, 1, 2, 3, 4, 5 when a digit may be repeated any number of times?
Find the total number of ways in which 20 balls can be put into 5 boxes so that first box contains just one ball ?
Evaluate each of the following:
8P3
Evaluate each of the following:
P(6, 4)
The number of permutations of n different things taking r at a time when 3 particular things are to be included is
How many numbers greater than 10 lacs be formed from 2, 3, 0, 3, 4, 2, 3 ?
If (n+2)! = 60[(n–1)!], find n
Evaluate the following.
`(3! + 1!)/(2^2!)`
If `""^(("n" – 1))"P"_3 : ""^"n""P"_4` = 1 : 10 find n
Determine the number of permutations of the letters of the word SIMPLE if all are taken at a time?
A student appears in an objective test which contain 5 multiple choice questions. Each question has four choices out of which one correct answer.
How will the answer change if each question may have more than one correct answers?
The number of arrangements of the letters of the word BANANA in which two N's do not appear adjacently is ______.
The number of words which can be formed out of the letters of the word ARTICLE, so that vowels occupy the even place is ______.
Let b1, b2, b3, b4 be a 4-element permutation with bi ∈ {1, 2, 3, .......,100} for 1 ≤ i ≤ 4 and bi ≠ bj for i ≠ j, such that either b1, b2, b3 are consecutive integers or b2, b3, b4 are consecutive integers. Then the number of such permutations b1, b2, b3, b4 is equal to ______.
