Quantitative Aptitude: Probability Questions – Set 18

1. In how many different ways the letter of ‘MORBID’ can be arranged ?
   780
   720
   620
   680
   none of these
   Option B
   required no. of ways=6!=720

    

2. When three coins are tossed simultaneously, then find the probability of getting at least one head.
   7/8
   1/8
   3/10
   6/15
   5/8
   Option A
   required no. of outcome= 3C1+ 3C2+ 3C3
   =3+3+1=7
   total no. of outcome=2^3=8
   probability=7/8

    

3. A bag contains 3 red balls, 4 black balls and 7 green balls. 3 balls are drawn randomly, then find the probability of getting all balls are of green colours.
   5/52
   9/52
   11/52
   15/52
   17/52
   Option A
   required no. of outcome= 7C3
   total no. of outcome= 14C3
   probability=(7C3)/ 14C3
   =7*6*5/14*13*12=5/52

    

4. When two dice are thrown simultaneously, then find the probability that sum of the digits on both the faces is 8.
   9/37
   7/36
   3/37
   5/36
   11/36
   Option D
   total no. of outcome=6^2=36
   required no. of outcome=(3,5), (5,3), (6,2), (2,6), (4,4)=5
   probability=5/36

    

5. When two dice are thrown simultaneously, then find the probability that sum of the digits is a multiple of 4.
   1/4
   3/10
   9/10
   13/36
   17/36
   Option A
   total no. of outcome=6^2=36
   required no. of outcome=(4,8,12)
   4=(2,2), (3,1), (1,3)
   8=(3,5), (5,3), (6,2), (2,6), (4,4)
   12=(6,6)
   probability=(3+5+1)/36
   =9/36=1/4

    

6. If 2 cards are picked randomly from a pack of 52 cards, then find the probability of getting both queen cards.
   5/221
   1/221
   9/221
   37/221
   38/221
   Option B
   required probability= (4C2)/(52C2)
   =1/221

    

7. How many 4 digit numbers can be formal by using (0,9), if repetition is not allowed such that unit digit of the number will always be 3 ?
   628
   220
   548
   346
   448
   Option E
   required number of 4 digit number=8*8*7=448

    

8. Find the probability of selecting 2 green balls out of 4 green and 3 red balls.
   5/7
   6/7
   4/7
   2/7
   1/7
   Option D
   required probability=(4C2)/(7C2)
   4*3/7*6=2/7

    

9. A basket contains 4 blue balls, 3 red balls, 4 green balls and 5 green balls. If 4 balls are picked at randomly, then find the probability that 2 are blue and 2 are yellow ?
   4/91
   6/91
   3/91
   9/96
   11/96
   Option C
   required probability=(4C2)*(5C2)/(16C4)
   = (4*3/2*1)*(5*4/2*1)/(16*15*14*13)/(4*3*2*1)
   =3/91
   

    

10. A bag contains 4 yellow, 5 blue and 6 green balls. If 3 balls are drawn at randomly, then find the probability that all ball is not yellow ?
    452/455
    454/455
    6/355
    451/455
    2/455
    Option D
    required probability=(15C3)-(4C3)/15C3
    =1-(4*3*2)/(15*14*13)=451/455

     

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