Q. A natural number is selected from 1 to 1000 at random, then the probability that a particular non-zero digit appears at most once, is
A) $\frac{243}{250}$
B) $\frac{13}{15}$
C) $\frac{11}{15}$
D) $\frac{239}{250}$
Explanation
(a)
There is only one two digit number not satisfying the given property. Again there are 27 three digit numbers not satisfying the given property. Hence, required probability
$= 1 - \frac{27 + 1}{1000} = \frac{243}{250}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.