Question

The number of five digit numbers having atleast one of their digits repeated is

• A. 900
• B. 1000
• C. 62784
• D. none of these

Answer 1

The correct option is C 62784

Total number of 5 digit numbers = $=9\times {10}^4=90000$

Number of digit numbers without nany repetition =

$=9\times 9\times 8\times 7\times 6=27216$

$\therefore$ Required number of 5 digit numbers in which atleast one of the digit repeats = 90000 - 27216 = 62784