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  • Question
  • Two dice are tossed. The probability that the total score is a prime number is:


  • Options
  • A.
    1
    6
  • B.
    5
    12
  • C.
    1
    2
  • D.
    7
    9

  • Correct Answer
  • 5
    12
     

    Explanation
    Clearly, n(S) = (6 x 6) = 36.

    Let E = Event that the sum is a prime number.

    Then E = { (1, 1), (1, 2), (1, 4), (1, 6), (2, 1), (2, 3), (2, 5), (3, 2), (3, 4), (4, 1), (4, 3),
          (5, 2), (5, 6), (6, 1), (6, 5) }

    n(E) = 15.

    ∴ P(E) = n(E) = 15 = 5 .
    n(S) 36 12


    Probability problems


    Search Results


    • 1. Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5?

    • Options
    • A.
      1
      2
    • B.
      2
      5
    • C.
      8
      15
    • D.
      9
      20
    • Discuss
    • 2. A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is:

    • Options
    • A.
      1
      22
    • B.
      3
      22
    • C.
      2
      91
    • D.
      2
      77
    • Discuss
    • 3. In 100 m race, A covers the distance in 36 seconds and B in 45 seconds. In this race A beats B by:

    • Options
    • A. 20 m
    • B. 25 m
    • C. 22.5 m
    • D. 9 m
    • Discuss
    • 4. In a game of 100 points, A can give B 20 points and C 28 points. Then, B can give C:

    • Options
    • A. 8 points
    • B. 10 points
    • C. 14 points
    • D. 40 points
    • Discuss
    • 5. A runs 1⅔ times as fast as B. If A gives B a start of 80 m, how far must the winning post be so that A and B might reach it at the same time?

    • Options
    • A. 200 m
    • B. 300 m
    • C. 270 m
    • D. 160 m
    • Discuss
    • 6. One card is drawn at random from a pack of 52 cards. What is the probability that the card drawn is a face card (Jack, Queen and King only)?

    • Options
    • A.
      1
      13
    • B.
      3
      13
    • C.
      1
      4
    • D.
      9
      52
    • Discuss
    • 7. Two cards are drawn together from a pack of 52 cards. The probability that one is a spade and one is a heart, is:

    • Options
    • A.
      3
      20
    • B.
      29
      34
    • C.
      47
      100
    • D.
      13
      102
    • Discuss
    • 8. A card is drawn from a pack of 52 cards. The probability of getting a queen of club or a king of heart is:

    • Options
    • A.
      1
      13
    • B.
      2
      13
    • C.
      1
      26
    • D.
      1
      52
    • Discuss
    • 9. What is the probability of getting a sum 9 from two throws of a dice?

    • Options
    • A.
      1
      6
    • B.
      1
      8
    • C.
      1
      9
    • D.
      1
      12
    • Discuss
    • 10. Two dice are thrown simultaneously. What is the probability of getting two numbers whose product is even?

    • Options
    • A.
      1
      2
    • B.
      3
      4
    • C.
      3
      8
    • D.
      5
      16
    • Discuss


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