NDA2016MathematicsPermutation and CombinationActual
What is the number of four-digit decimal numbers ( 1) in which no digit is repeated?
Options
- A3024
- B4536
- C5040
- DNone of the above
Correct answer
B. 4536
Step-by-step solution
Let the given 4 digit decimal number is * Places after decimal can be filled in the following ways: array |l|l|l|l| 7 & 8 & 9 & 9 array Total number of ways =7 8 9 9=4536