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Two-digit even number

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deepoe Really wants to Beat The GMAT! Default Avatar
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Two-digit even number Post Tue Mar 03, 2009 3:40 am
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  • Lap #[LAPCOUNT] ([LAPTIME])
    A two-digit even number is such that reversing its digits creates an odd number greather than the original number. Which one of the following cannot be the first digit of the original number?

    A. 1
    B. 3
    C. 5
    D. 7
    E. 9

    OA = 9

    I need to make a even number of the numbers that are given?

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    piyush_nitt GMAT Destroyer! Default Avatar
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    Post Tue Mar 03, 2009 4:10 am
    deepoe wrote:
    A two-digit even number is such that reversing its digits creates an odd number greather than the original number. Which one of the following cannot be the first digit of the original number?

    A. 1
    B. 3
    C. 5
    D. 7
    E. 9

    OA = 9

    I need to make a even number of the numbers that are given?
    Nope , You don't need to make an even number.

    Question states that original number is a 2 digit number and its even.

    Therefore , unit digit of 2 digit number has to be either 2,4,6 or 8. (cannot be zero because on reversing , the number no longer would be 2 digit)

    NOW

    Question also states that on reversing the digit becomes odd and it is greater than previous number (This is the KEY). say for e.g original number was 12 then now the number is 21. which is correct.

    So basically we need to find out the number at Tens place of original number that doesnot satisfy above 2 statements.

    As answer is 9 , I am justifying the answer here .

    Original numbers are , if tens digit is 9
    92,94,96,98

    when you reverse it , it becomes 29,49,69,89 which is contradictory and Hence the answer.

    Hope that helps.

    Thanked by: deepoe

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