Q. 25.0( 4 Votes )

Mark the correct

Answer :

Total number of five-digit telephone numbers = 105 = 100000.


When no digit is repeated, then the number of five-digit telephone numbers = 10P5


[as, 5 digits among 10 digits can be arranged in 10P5 ways]


=10×9×8×7×6


= 30240


So, the number of five-digit telephone numbers having at least one of their digits repeated is = 100000 – 30240


= 69760.


The discussion can be shown pictorially as:


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses
RELATED QUESTIONS :

Four letters E, KRD Sharma - Mathematics

. There are 6 iteRD Sharma - Mathematics

How many permutatRD Sharma - Mathematics

Find the total nuRD Sharma - Mathematics

In how many ways RD Sharma - Mathematics

From among the 36RD Sharma - Mathematics

How many differenRD Sharma - Mathematics

How many three-diRD Sharma - Mathematics

In how many ways RD Sharma - Mathematics

How many three-diRD Sharma - Mathematics