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?
Options:
A) 1
B) 2
C) 4
D) Data inadequate
E) None of these
Solution   Let the ten's digit be x and unit's digit be y. Then, (10x + y) - (x + y) = 9 or x = 1.   From this data, we cannot find y, the unit's digit. So the data is inadequate.   Answer Data inadequate
<result>D</result>
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?