Multiple choice

A numerical problem is given to three students John, Johny and Janet, whose chances of solving it are 1/3, 1/5 and 1/6 respectively. The probability that the problem will be solved is

  1. 89/90

  2. 5/9

  3. 7/15

  4. 7/10

  5. 1/90
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Probability that John can solve the problem is 1/3. Probability that John cannot solve the problem is (1 - 1/3) = 2/3. Probability that Johny can solve the problem is 1/5. Probability that Johny cannot solve the problem is (1-1/5) = 4/5. Probability that Janet can solve the problem is 1/6. Probability that Janet cannot solve the problem is (1 - 1/6) = 5/6. The probability that they together cannot solve the problem is = 2/3 × 4/5 × 5/6 = 4/9. Therefore, the required probability that the problem will be solved is = (1 - 4/9) = 5/9.

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