# A customer forgets a four - digit 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 trails necessary to obtain the correct code.

In the question, we have to find the possible number of 4 digit numbers formed by the numbers 3, 5, 6, 9 when repetition of digits is not allowed.

We will use the concept of multiplication because there are four sub jobs dependent on each other because a number appearing on any one place will not appear in any other place because all the four numbers are to be used as they are in the code.

The first position from the left will have four choices; the second position will have three choices because one number is consumed in the first position , the number of choices will decrease by one as we keep on going right side.

The number of ways in which we can form four-digit numbers with the help of given data is 4 × 3 × 2 × 1 = 24

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Circular permutations61 mins
Challenging Quiz on P&C | Test Yourself55 mins
Permutations & Combinations | Analyze your learningFREE Class
Understand Permutations like never before60 mins
Check Your progress Part 2| Interactive Quiz: Permutation & CombinationFREE Class
Lecture on Combinations49 mins
Interactive Quiz on Division and distribution of objects17 mins
Interactive Quiz on Combinations50 mins
Division and distribution of objects58 mins
Interactive Quiz on Combinations-0253 mins
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
view all courses