Out of all the 2-digit integers between 1 and 100, a 2-digit number has to be…

20132013

Out of all the 2-digit integers between 1 and 100, a 2-digit number has to be selected at random. What is the probability that the selected number is not divisible by 7?

  1. A.

    13/90

  2. B.

    12/90

  3. C.

    78/90

  4. D.

    77/90

Attempted by 131 students.

Show answer & explanation

Correct answer: D

There are a total of 90 two digit numbers, out of them 13 are divisible by 7, these are 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98.

Therefore, the probability that the selected number is not divisible by 7 = 1 – 13/90 = 77/90.

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