Quantitative Aptitude: Probability Questions – Set 10

  1. A bag contains 12 white and 18 black balls. Two balls are drawn in succession without replacement.
    37/145
    35/142
    33/141
    36/145
    31/140
    Option D
    Required probability,
    =(2/5)×(18/29)
    =36/145

     

  2. 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?
    1/4
    2/5
    3/8
    4/9
    2/7
    Option C
    Required probability
    =24/4^3
    =3/8

     

  3. A card is drawn from a pack of 52 cards. The card is drawn at random. What is the probability that it is neither a spade nor a Jack?
    8/11
    5/7
    4/5
    9/13
    8/13
    Option D
    Probability of getting spade or a jack
    =(13+3)/52
    =4/13
    So probability of getting neither spade nor a jack
    =1−4/13
    =9/13

     

  4. A bag contains 5 red and 3 green balls. Another bag contains 4 red and 6 green balls. If one ball is drawn from each bag. Find the probability that one ball is red and one is green.
    17/42
    21/40
    19/44
    20/43
    19/41
    Option B
    Required probability = 3/8+3/20 = 21/40

     

  5. Two brother X and Y appeared for an exam. The probability of selection of X is 1/7 and that of B is 2/9. Find the probability that both of them are selected.
    4/65
    2/63
    2/65
    3/62
    2/61
    Option B
    Probability =(1/7)*(2/9)
    =2/63

     

  6. Two brothers appeared for an exam. The probability of each of them getting selected is 1/4 and 1/6 respectively. Find the probability that only one of the two are selected.
    1/7
    1/5
    1/4
    1/2
    1/3
    Option E
    Probability that only of the two are selected
    = [(1/4)*(5/6)]+[(3/4)*(1/6)]= [5/24]+[3/24]= 8/24
    = 1/3

     

  7. A card is selected at random from a pack of cards. After replacing it, another draw is made. Find the probability that the first card is a spade and the second is a club.
    1/18
    1/16
    1/17
    1/13
    1/15
    Option B
    P(drawing a spade) = 13/52 = 1/4
    P(drawing a club) = 1/4
    Probability = (1/4)*(1/4) = 1/16

     

  8. A bag contains 2 red, 4 blue and 6 green balls. If one ball is drawn from the bag, what is the probability that it is red or green?
    2/3
    5/6
    5/9
    3/7
    2/5
    Option A
    Required Probability = 8/12 = 2/3

     

  9. Two friends appear for an interview. The probability of each of them getting selected is 1/5 and 1/6 respectively. Find the probability that both are selected.
    1/35
    1/33
    1/30
    1/31
    1/29
    Option C
    P(both being selected)
    = (1/5)*(1/6)
    = 1/30

     

  10. Three unbiased coins are tossed. What is the probability of getting at most two heads ?
    6/7
    3/5
    8/9
    7/8
    4/5
    Option D
    Probability = 7/8

     


Related posts

Leave a Comment