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put this solution on YOUR website!let the two digit number be xy
such that 10x +y =xy
now as per question
x+y = 11 -----eq1
10y +x = 10x+y+9 ------eq2
or 9y-9x=9
multiply eq1 with9
so we have
9x +9y = 99 ----eq3
add eq3 and eq2 we have
9x +9y = 99
9y -9x = 9
---------------
18y = 108
y = 108/18 = 6
so x = 5 ( by substituting the value of y in eq1)
(Ans)