Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
Evaluate `(n!)/((n-r)!)` when n = 6, r = 2
How many 3-digit numbers can be formed by using the digits 1 to 9 if no digit is repeated?
How many 3-digit even numbers can be made using the digits 1, 2, 3, 4, 6, 7, if no digit is repeated?
From a committee of 8 persons, in how many ways can we choose a chairman and a vice chairman assuming one person cannot hold more than one position?
In how many ways can the letters of the word PERMUTATIONS be arranged if the words start with P and end with S.
In how many ways can three jobs I, II and III be assigned to three persons A, B and C if one person is assigned only one job and all are capable of doing each job?
How many numbers of six digits can be formed from the digits 0, 1, 3, 5, 7 and 9 when no digit is repeated? How many of them are divisible by 10 ?
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?
The number of different signals which can be given from 6 flags of different colours taking one or more at a time, is
If in a group of n distinct objects, the number of arrangements of 4 objects is 12 times the number of arrangements of 2 objects, then the number of objects is
In a room there are 12 bulbs of the same wattage, each having a separate switch. The number of ways to light the room with different amounts of illumination is
How many numbers lesser than 1000 can be formed using the digits 5, 6, 7, 8, and 9 if no digit is repeated?
The number of ways to arrange the letters of the word “CHEESE”:
The number of permutation of n different things taken r at a time, when the repetition is allowed is:
Three men have 4 coats, 5 waist coats and 6 caps. In how many ways can they wear them?
A coin is tossed 8 times, how many different sequences containing six heads and two tails are possible?
The number of arrangements of the letters of the word BANANA in which two N's do not appear adjacently is ______.
The number of 5-digit telephone numbers having atleast one of their digits repeated 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 ______.
