SOLUTION: The sum of the digits of a 2-digit number is 8.The number obtained by interchanging the digits exceeds the given number by 18. Find the given number.

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Question 702268: The sum of the digits of a 2-digit number is 8.The number obtained by interchanging the digits exceeds the given number by 18. Find the given number.
Answer by neatmath(302) About Me  (Show Source):
You can put this solution on YOUR website!

This is a tricky one, but let's try it:

Let x be the tens digit of the number.

Let y be the ones digit of the number.

Then we have:

Equation 1: x%2By=8 given

Equation 2: x%2By%2A10=18%2Bx%2A10%2By given

x%2B10y=18%2B10x%2By

-9x%2B9y=18 call this Equation 3

Let's use elimination help us solve this system:

9x%2B9y=72 Equation 1 multiplied by 9

Now add Equation 1 to Equation 3:

18y=90

y=5

If y=5, it is easy to see that x=3

Thus, our two-digit number is 35.

Check:

53=18%2B35???

53=53 YES

The tricky part is getting the give Equation 2 correct.

I hope this helps! Keep practicing! :)

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