Question

in a two digit number the sum of the two digit is 7 .if the number with the order of the digit reversed is 28 greater then twice the unit's digit of the original number,find the number.

Answer 1

Let one digit be x
then , the other digit will be ' 7 - x '
you can either take x or 7 - x at unit's place .
A.T.Q
10(7 - x ) + 1 ( x ) = 28 + 2 ( 7 - x )
Solving this , we get 
70 - 10x +x = 28 +14 - 2x
42 - 9x = 14 - 2x
28 = 7x
Therefore , x = 4
and the other digit will be (7- x) = 7- 4 = 3
the number will be either 43 or 34 depending on which digit you chose at the unit's place.