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  • Question
  • Find the probability that one ball is white when two balls are drawn at random from a basket that contains 9 red, 7 white and 4 black balls.


  • Options
  • A. 18/95
  • B. 18/190
  • C. 1/2
  • D. 91/190

  • Correct Answer
  • 91/190 

    Explanation

    Total number of elementary events = 20 C 2  ways =190

     

    There are 7 white balls out of which one white can be drawn in 7 C 1  ways and one ball from remaining 13 balls can be drawn in 13 C 1  ways.

     

    So,favourable events =  7 C 1 * 13 C 1

     

    Therfore,required probability = ( 7 C 1 * 13 C 1 )/ 20 C 2 =91/90


  • Probability problems


    Search Results


    • 1. One card is drawn from deck of 52 cards, each of the 52 cards being equally likely to be drawn. Find the probability that the ball drawn is red.

    • Options
    • A. 1/3
    • B. 1/2
    • C. 1/4
    • D. 1/6
    • Discuss
    • 2. Find the probability of selecting exactly 2 children when four persons are choosen at random from a group of 3 men, 2 woman and 4 children.

    • Options
    • A. 9/29
    • B. 10/21
    • C. 12/21
    • D. 14/19
    • Discuss
    • 3. What is the probability that a couple with four children have atleast one girl?

    • Options
    • A. 0.0625
    • B. 0.9375
    • C. 0.5
    • D. 0.0257
    • Discuss
    • 4. The probability that a card drawn at random from the pack of playing cards may be either a queen or an ace is:

    • Options
    • A. 9/13
    • B. 11/13
    • C. 2/13
    • D. None of these
    • Discuss
    • 5. The probabiltiy that throw of two dice yields a total of 5 or 6 is:

    • Options
    • A. 2/14
    • B. 5/18
    • C. 3/4
    • D. 1/4
    • Discuss
    • 6. A six-sided die with faces numbered 1 through 6 is rolled three times. What is the probability that the face with the number 6 on it will not face upward on all the three rolls?

    • Options
    • A. 215/216
    • B. 1/216
    • C. 215/256
    • D. 1/52
    • Discuss
    • 7. In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:

    • Options
    • A. 21/46
    • B. 1/5
    • C. 3/25
    • D. 1/50
    • Discuss
    • 8. What is the probabiltiy of getting a mutliple of 2 or 5 when an unbiased cubic die is thrown?

    • Options
    • A. 1/3
    • B. 1/2
    • C. 2/3
    • D. 1/6
    • Discuss
    • 9. What is the probability that it is either a heart card or diamond card, when a card is drawn from a well shuffled standard pack of 52 playing cards?

    • Options
    • A. 1
    • B. 1/2
    • C. 3/4
    • D. 1/3
    • Discuss
    • 10. From well shuffled standard pack of 52 playing cards,one card is drawn. What is the probability that it is either a red card or black card?

    • Options
    • A. 1/2
    • B. 3/4
    • C. 1
    • D. 1/3
    • Discuss


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