Question 989803
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Let a and b are the digits of your number  n,  so that  n = 10a + b.


The number after interchanging digits is  10b + a.


Then you have the system of two equations for the unknowns  a  and  b:


{{{system(a+b = 10,

(10b +a) - (10a + b) = 36)}}}.


Now,  simplify it:


{{{system (a+b= 10,

9b - 9a = 36)}}}. 


Simplify one more time:


{{{system (a+b= 10,

b - a = 4)}}}. 


Solve it.


b=7,  a=3.


The number is  10a + b = 10*3+7 = 37.


<B>Answer</B>. &nbsp;37.