Question

The sum of the digits of a two-digit number is $9$ less than the number. Which of the following digits is at tenth's place of the number?

• A. $1$
• B. $2$
• C. $4$
• D. Data inadwquate

Answer 1

Answer: (A)

$1$

Let the two digit number is $xy$. [$x$ in tenth place and $y$ in the unit's place]

So number is $10x+y$.

Then according to the problem,

$x+y=10x+y-9$

or, $9x=9$

or, $x=1$.

So the tenth's place digit is $1$.