Question 873151
Ten's digit=x
Unit's digit=y
x+y=12----(1)
Number=10x+y
On reversing, it becomes x+10y
x+10y-(10x+y)=36
-9x+9y=36
-x+y=4---(2)
x+y=12---(1)
Adding both equations, 
2y=16
y=8
Plugging in y=8 in eq (1)
x+8=12
x=4

Hence the number=10*4+8=48
-------------------------Peace out, hun :*---------------