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- Question
- What is the possibility of getting at least 6 heads, if eight coins are tossed simultaneously?
Options- A. 37/256
- B. 25/57
- C. 1/13
- D. None of these
- Correct Answer
- 37/256
ExplanationRequired probability = Probability of getting 2 tails + Probability of getting 1 tail + Probability of getting no tail.
= 8C2 x 1/256 + 8C1 x 1/256 + 8C0 x 1/256
= 37/256 - 1. Two unbiased dice are thrown simultaneously. the probability of getting the sum divisible by 3, is?
Options- A. 11/36
- B. 12/36
- C. 13/36
- D. 17/36 Discuss
- 2. Cards are down at random from a pack of 200 cards numbered 1 to 200. Find the probability of drawing a number which is a perfect cube?
Options- A. 1/40
- B. 3/40
- C. 7/40
- D. 19/40 Discuss
- 3. when three coins are tossed together the probability that all coins have the same face up, is?
Options- A. 1/3
- B. 1/6
- C. 1/8
- D. 1/12 Discuss
- 4. Two packs of card are thoroughly mixed and shuffled and two cards are drawn at random, one after the other. What is the probability that both of them are jack?
Options- A. 1/13
- B. 2/13
- C. 7/1339
- D. 1/169 Discuss
- 5. A brother and sister appear for an interview against two vacant posts in an office. The probability of the brother's selection is 1/5th and that of the sister's selections is 1/3rd. What is the probability that one of them is selected?
Options- A. 1/5
- B. 2/5
- C. 1/3
- D. 2/3 Discuss
- 6. A and B aim a target. The Probability that A hits the target is 5/7 and B hits the target in 7/10. What is the probability that exactly one of them hits the target?
Options- A. 21/10
- B. 29/70
- C. 31/70
- D. 33/70 Discuss
- 7. A bag contains 5 white, 7 red and 8 black balls. If 4 balls are drawn one by one with replacement, what is the probability that all are white?
Options- A. 1/256
- B. 1/16
- C. 4/20
- D. 4/8 Discuss
- 8. There are 8 blue and 4 white balls in a bag . A ball is drawn at random. Without replacing it another ball is drawn. Find the probability that both the balls drawn are blue?
Options- A. 7/33
- B. 14/33
- C. 11/33
- D. 2/33 Discuss
- 9. Two dice are thrown simultaneously. What is the probability of getting a number other than 4 on any dice?
Options- A. 25/36
- B. 1/3
- C. 17/36
- D. 2/3 Discuss
- 10. Number 1 to 25 are marked on tokens of equals size one on each. A token is drawn at random. Find the probability of getting a number divisible by both 2 and 3?
Options- A. 4/25
- B. 7/25
- C. 2/25
- D. 9/25 Discuss
Probability problems
Search Results
Correct Answer: 12/36
Explanation:
n(S) = 6 x 6 = 36
n(E) = (1, 2) (2, 1), (1, 5) (2, 4) (3, 3) (4, 2) (5, 1) (3, 6) (4, 5) (5, 4) (6, 3) (6, 6) = 12
? P(E) = 12/36
Correct Answer: 1/40
Explanation:
Total number of ways of selecting 1 card from 200 cards is 200C1 ways.
Let E be an event of drawing a number which is a perfect cube.
E = {1, 8, 27, 64, 125 }
? P(E) = n(E) / n(S)
= 5C1 / 200C1 = 5/200 = 1/40
Correct Answer: 1/8
Explanation:
Probability of head or a tail on upper side of coin = 1/2
? Probability of getting same face on all three coins = 1/2 x 1/2 x 1/2
= 1/8
Correct Answer: 7/1339
Explanation:
Total number of cards = 104
Total number of jacks = 8
? Probability for the jack in first draw = 8/104
and probability for the jack in second draw = 7/103
Since, both are independence events.
? Required probability = 8/104 x 7/103 = 7/1339
Correct Answer: 1/3
Explanation:
One of them can be selected in the following ways.
Brother is selected and sister is not selected.
or
Brother is not selected and sister is selected.
? Required probability = 1/5 x 2/3 + 4/5 x 1/3
= 2/15 + 4/15 = 6/15 = 2/5
Correct Answer: 29/70
Explanation:
Required probability = P(A). P(B) + P (A ) . P(B)
= 5/7 . 3/10 + 2/7 . 7/10
= 29/70
Correct Answer: 1/256
Explanation:
Probability that first ball drawn is white = 5C1 = 1/4
Since, balls are drawn with replacement, hence all the four events will have equal probability.
Therefore, required probability = 1/4 x 1/4 x 1/4 x 1/4 = 1/256
Correct Answer: 14/33
Explanation:
Total number of balls in the bag = 12
Probability of drawing one blue ball in the first draw P(E1) = 8C1 / 12C1
= 8/12 = 2/3
After the first drawn of a blue ball, now there are 7 blue and 4 white ball in the bag. Total number of the balls in the bag is 11.
Probability of drawing one blue ball in the second drawn = P(E2) = 7C1 /11C1 = 7/11
? Probability that both are blue P(E1 ? E2) = P(E1) x P(E2)
= 2/3 x 7/11 = 14 / 33
Correct Answer: 25/36
Explanation:
Here, n(S) = 6 x 6 = 36 and E = Event of getting a number other than 4 on any dice
= {(1, 1), (1, 2), (1, 3), (1, 5), (1, 6), (2, 1), (2, 2) , (2, 3) , (2, 5), (2, 6), (3, 1), (3, 2), (3, 3), (3, 5), (3, 6), (5, 1) , (5, 2) , (5, 3), (5, 5), (5, 6), (6, 1), (6, 2), (6, 3), (6, 5), (6, 6) }
? P(E) = n(E) / n(S) = 25/36
Correct Answer: 4/25
Explanation:
Total number of ways of selecting one number from 25 number is 25C1 ways.
Let E be the event of drawing a number divisible by both 2 and 3
i.e., (if a number is divisible by both 2 and 3, it is divisible by 6 also)
E = {6, 12, 18, 24}
? Required probability = P(E) = n(E) / n(S) = 4/25
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