1.  If the number obtained on interchanging the digits of a two-digit number is 18 more than the original number and the sum of the digits is 8, then what is the original number ?

A. 26
B. 35
C. 53
D. Cannot be determined
E. None of these

Answer: Option B

Explanation:

Let ten's digit = x Then, unit's digit = (8 - x).
∴ [10(8 - x) + x] - [10x + (8-x)] = 18
<=> 18x = 54
<=> x = 3.
So, ten's digit = 3 and unit's digit = 5.
Hence, original number = 35.