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- Question
- All the girls are not sitting together?
Options- A. 41/42
- B. 39/42
- C. 31/42
- D. 31/35
- Correct Answer
- 41/42
ExplanationRequired probability = 1- probability that all the girls sit together
= 1 - 1/42 = 41/42 - 1. If three marbles are picked at random, what is the probability that either all are green or all are red?
Options- A. 7/44
- B. 7/12
- C. 5/12
- D. 1/44 Discuss
- 2. If one cap is picked at random, what is the probability that it is either blue or yellow?
Options- A. 2/9
- B. 1/4
- C. 3/8
- D. 6/11 Discuss
- 3. An elevator starts with 5 passengers and stops at 8 different floors if the house. Find out the probability of all the 5 passengers alighting at different floors.
Options- A. 101/512
- B. 105/512
- C. 107/512
- D. 109/512 Discuss
- 4. Four boys and three girl stand in queue for an interview. The probability that they stand in alternate position is
Options- A. 1/34
- B. 1/35
- C. 1/17
- D. 1/68 Discuss
- 5. An anti-aircraft gun can take a maximum of four shots at an enemy plane moving away from it ,The probability of hitting the plane at the first, second, third and fourth shots are 0.4, 0.3, 0.2, and 0.1 respectively. What is the probability that the plane is hit when all the four shots are fired?
Options- A. 0.4379
- B. 0.6872
- C. 0.6976
- D. 0.3507 Discuss
- 6. All the boys are not sitting together?
Options- A. 3/35
- B. 43/49
- C. 41/42
- D. 1/42 Discuss
- 7. All the girls are sitting together.
Options- A. 1/42
- B. 41/42
- C. 3/35
- D. 1/42 Discuss
- 8. All the boys are sitting together.
Options- A. 3/42
- B. 41/42
- C. 3/35
- D. 1/42 Discuss
- 9. A fair coin is tossed 100 times, The probability of getting head an odd number of times is?
Options- A. 1/4
- B. 2/3
- C. 1/2
- D. 3/4 Discuss
- 10. Out of 15 students studying in a class, 7 are from Maharastra, 5 are from Karnataka and 3 are from Goa, Four students are to be selected at random. What are the chances that at least one is from Karnataka?
Options- A. 12/13
- B. 11/13
- C. 10/15
- D. 1/15 Discuss
Probability problems
Search Results
Correct Answer: 1/44
Explanation:
Total number of ways of selection of 3 marbles out of 12
= n(S) = 12C3 = 220
Total number of favorable events = n(E)
= 3C3 + 4C3 = 1 + 4 = 5
? Required probability
= 5/220 = 1/44
Correct Answer: 1/4
Explanation:
Total number of caps = 12
n(s) = 12c1 = 12
Out of ( 2 blue + 1 yellow) caps, number of ways to pick one cap n(E) = 3c1 = 3
? Required probability = p(E) = n (E) / n(s) = 3/12 = 1/4
Correct Answer: 105/512
Explanation:
Required probability = favorable number of cases/ total number of
=8P5 / 8 5 = 105/512
Correct Answer: 1/35
Explanation:
Total number of possible arrangement for 4 boy and 3 girls in a queue = 7!
when they occupy alternate position then the arrangement would be like
BGBGBGB. Thus the total number of possible arrangement = 4! x 3!
? Required probability = 4! x 3! / 7!
= (4 x 3 x 2 x 3 x 2) / (7 x 6 x 5 x 4 x 3 x 2) = 1/35
Correct Answer: 0.6976
Explanation:
First we find the probability that the plane is not hit
= (1 - 0.4) ( 1 - 0.3) (1 - 0.2) (1 - 0.1)
= 0.6 x 0.7 x 0.8 x 0.9 = 0.3024
? probability that the plane is hit = 1 - 0.3024
= 0.6976
Correct Answer: 41/42
Explanation:
Required probability = 1- probability that all the boys sit together
= 1- 1/42 = 41/42
Correct Answer: 1/42
Explanation:
We have, 5 boys and 5 girls.
Since, all the girls are sitting together, we consider them as one. Now, we can arrange 5 boys and 1 girl in 6! ways and these 5 girls (whom we considered as one) can also be arranged in 5! ways.
? Favorable number of ways = 6!5!
and total number of ways to arrange 5 boys and 5 girls = 10!
? Required probability 6!5!/10! = 1/42
Correct Answer: 1/42
Explanation:
Required probability = 6!5!/10! = 1/42
Correct Answer: 1/2
Explanation:
n(S) = 2100
n(E) = No. of favourable ways = 100C1 + 100C3 + ... 100 C99 = 2100-1 = 299
[? nC1 + nC3 + nC5 + ........................... = 2n-1 ]
? P(E)= n(E)/n(S) = 299/2100 = 1/2
Note : The given case can be generalised as "If a unbiased coin is tossed 'n' times, then the chance that the head will present itself an odd number of times is 1/2. "
Correct Answer: 11/13
Explanation:
Total possible ways of selecting 4 students out of 15 students = 15C4
= (15 x 14 x 13 x 12) / (1 x 2 x 3 x 4) = 1365
The no. of ways of selecting 4 students in which no students belongs to karnataka = 10C4
? Number of ways of selecting atleast one student from karnataka = 15C4 - 10C4 = 1155.
? Required probability
= 1155 / 1365 = 77 / 91 = 11 / 13
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