The sum of the digits of a two-digit number is 9 less than the number. Which of the following digits is at… · ABC26GN1736
Subject: General Aptitude · Chapter: Problems on Numbers
The sum of the digits of a two-digit number is 9 less than the number. Which of the following digits is at unit's place of the number?
(a)1
(b)2
(c)4
(d)Data inadequate
Answer
Answer (as printed): D
Explanation
Let the ten's digit be $x$ and unit's digit be $y$. Then, $(10 x+y)-(x+y)=9$ or $x=1$. From this data, we cannot find $y$, the unit's digit. So, the data is inadequate.
Explanation as extracted from the printed page; notation may be imperfect.