SOLUTION: The sum of the digits of a two digit number is 5. On reversing the digits of the number, the octane number exceeds the original number by 9. Find the original number.

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Question 888311: The sum of the digits of a two digit number is 5.
On reversing the digits of the number, the octane
number exceeds the original number by 9. Find the
original number.

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

let x be the tens digit
let y be the units/ones digit
the sum of the digits of a two digit number is 5, so we
x+%2B+y+=+5
when the digits are reversed, the number is 9 more than the original
since x is your tens digit, its value is 10x
so you have the value of your original number 10x+%2B+y
when you reversed it, the new number is 10y+%2B+x}
we have 10y+%2B+x+=+9+%2B+10x+%2B+y+}
manipulate the equation above this sentence:
9y+-+9x+=+9} or
y+-+x+=+1
solve x and y with the equation from the top, which is x+%2B+y+=+5
y+-+x+=+1
x+%2B+y+=+5
_____________________add both and we get
2y+=+6 after adding two equations, then
highlight%28y+=+3%29
to solve for x, plug solution for y in one of the equations above
x+%2B+y+=+5

x+%2B+3=+5+
highlight%28x+=+2+%29
hence the number is highlight%2823%29
if the digits are reversed, the number is 32 which is 9 more than the number 23