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2009 AMC 10B Problem 19

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2009 AMC 10B Problem 19AMC 10 Step by Step
Name:                             Date: September 13, 2026
Basic Counting · difficulty 3 of 5 · about 4 min · position P16-20

A particular 1212 -hour digital clock displays the hour and minute of a day. Unfortunately, whenever it is supposed to display a 11 , it mistakenly displays a 99 . For example, when it is 1:16 PM the clock incorrectly shows 9:96 PM. What fraction of the day will the clock show the correct time?

  1. A)

    12\frac 12

  2. B)

    58\frac 58

  3. C)

    34\frac 34

  4. D)

    56\frac 56

  5. E)

    910\frac 9{10}

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