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  • Question
  • A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?


  • Options
  • A. 10/21
  • B. 11/21
  • C. 1/2
  • D. 2/7

  • Correct Answer
  • 10/21 

    Explanation

    Total number of balls = (2 + 3 + 2) = 7.

     

    Let S be the sample space.

     

    Then, n(S) = Number of ways of drawing 2 balls out of 7 = 7 C 2  = 21

     

    Let E = Event of drawing 2 balls, none of which is blue.

     

    n(E) = Number of ways of drawing 2 balls out of (2 + 3) balls = 5 C 2  = 10

     

    Therefore, P(E) = n(E)/n(S) = 10/ 21.


  • Probability problems


    Search Results


    • 1. A number X is chosen at random from the numbers -3, -2, -1, 0, 1, 2, 3. What is the probability that |X|<2

    • Options
    • A. 3/7
    • B. 3/4
    • C. 4/5
    • D. 5/7
    • Discuss
    • 2. In a simultaneous throw of pair of dice. Find the probability of getting the total more than 7.

    • Options
    • A. 1/2
    • B. 5/12
    • C. 7/15
    • D. 3/12
    • Discuss
    • 3. Two dice are rolled simultaneously. Find the probability of getting the sum of numbers on the on the two faces divisible by 3 or 4?

    • Options
    • A. 3/7
    • B. 7/11
    • C. 5/9
    • D. 6/13
    • Discuss
    • 4. What is the probability that a number is divisible by 4?

    • Options
    • A. 2
    • B. 1/2
    • C. 1/4
    • D. 1
    • Discuss
    • 5. The probability that z lies between 0 and 3.01

    • Options
    • A. 0.4987
    • B. 0.5
    • C. 0.9987
    • D. 0.1217
    • Discuss
    • 6. An unbiased die is tossed.Find the probability of getting a multiple of 3.

    • Options
    • A. 1/3
    • B. 1/2
    • C. 3/4
    • D. 3/2
    • Discuss
    • 7. In a bag which contains 40 balls, there are 18 red balls and some green and blue balls. If two balls are picked up from the bag without replacement, then the probability of the first ball being red and second being green is 3/26. Find the number of blue balls in the bag.

    • Options
    • A. 16
    • B. 12
    • C. 10
    • D. 14
    • Discuss
    • 8. There are four hotels in a town. If 3 men check into the hotels in a day then what is the probability that each checks into a different hotel?

    • Options
    • A. 1/2
    • B. 3/4
    • C. 4/7
    • D. 3/8
    • Discuss
    • 9. In a race, the odd favour of cars P,Q,R,S are 1:3, 1:4, 1:5 and 1:6 respectively. Find the probability that one of them wins the race.

    • Options
    • A. 319/420
    • B. 27/111
    • C. 114/121
    • D. 231/420
    • Discuss
    • 10. 14 persons are seated around a circular table. Find the probability that 3 particular persons always seated together.

    • Options
    • A. 11/379
    • B. 21/628
    • C. 24/625
    • D. 26/247
    • Discuss


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