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Math Help - Simultaneous equation word problem

  1. #1
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    Simultaneous equation word problem

    The sum of a 2 digit number is 9. If the number is doubled, then decreased by 36, the answer is the original number with the digits reversed. Find the number.

    I'm really amazed I couldn't figure out this problem, even though I've done this kind of problem before.
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  2. #2
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    Never mind, sorry. I realized how to express the number as a sum. That's what I struggled a long time about.
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  3. #3
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    Hi chengbin

    Let the number be xy
    "The sum of a 2 digit number is 9" ------> x + y = 9

    "If the number is doubled, then decreased by 36, the answer is the original number with the digits reversed" ------> 2(10x + y) - 36 = 10y + x

    EDIT : I was late.
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  4. #4
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    Can you please tell me how did you get the 10 in-front of x and y?
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  5. #5
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    Hi unstopabl3

    Simple example : let the number be 35, so x = 3 and y = 5

    35 = 10x + y
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  6. #6
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    Got, it!
    It's a two digit number, sorry for my haste at reading the question
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