Question

100 tickets are numbered as 00, 01, 02 ..... 09,10, 11, 12, ..... 99. Out of them, one ticket is drawn at random. The probability that the sum of the digits of the number on the ticket is 9 is

• A. $\frac{7}{100}$
• B. $\frac{9}{100}$
• C. $\frac{1}{10}$
• D. $\frac{1}{100}$

Answer 1

The correct option is C $\frac{1}{10}$

Let the digits be x and y.
$x+y=9$ can be obtained in the following ways:
$(x+y)=(0,9),(1,8),(2,7),(3,6),(4,5),(5,4),(6,3),(7,2),(8,1),(9,0)$
Thus, there are $10$ favorable cases out of $100$ cases.
Therefore, required probability = $\frac{10}{100}=\frac{1}{10}$