Question

A three digit number is selected at random from the set of all three digit numbers. The probability that the selected number has all the three digits the same is

• A. $\frac{1}{9}$
• B. $\frac{1}{10}$
• C. $\frac{1}{50}$
• D. $\frac{1}{100}$

Answer 1

The correct option is D $\frac{1}{100}$

Three digit numbers are $100,101,...,999$
Total numbers $=900$
Three digit number (which have all same digits) are $111,222,333,...999$
$\therefore$ Favorable number $=9$
$\therefore$ Required probability $=\frac{9}{900}=\frac{1}{100}$