# 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

1. slot gacor