Question
Sun August 19, 2012 By: Joshua
 

The sum of the digits of a two digit number is 12. The number obtained by reversing its digits exceeds the given number by 18. Then the number is______

Expert Reply
Sun August 19, 2012
Let the one's digit and ten's digt be x and y respectively.
From the given conditions, we have:
 
x + y = 12
10y + x + 18 = 10x + y   or   9y - 9x + 18 = 0  or  y - x = -2
 
Adding the above two equations, we get,
2y = 10
y = 5
 
So, x = 12 - 5 = 7
 
Thus, the required number is 57.
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