<PRE><B>Question 601346</B>
let x be the ones digit and y be the tenth digit
xy=35
the number is equal to 10y+x
if 18 is added
10y +x+ 18 
digit are interchanged so the number is xy, 10x+y
so 10y +x+ 18 = 10x+y
solve the two equations
9y-9x+18=0
y-x-2=0
x=y-2
xy=35
(y-2)(y)=35
y^2 -2y-35 =0
(y-7) (y+5) =0
y=7 so x = 5
y = -5 is rejected since -5 is negative
the number is 35


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