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- Question
- In a bag containing three balls, a white ball was placed and then one ball was taken out at random. What is the probability that the extracted ball would turn on to be white, if all possible hypothesis concerning the colour of the balls that initially in the bag were equally possible?
Options- A. 5/8
- B. 3/4
- C. 1/2
- D. 3/8
- Correct Answer
- 5/8
ExplanationSince, all possible hypothesis regarding the colour of the balls are equally likely, therefore these could be 3 white balls, initially in the bag.
? Required probability = 1/4 [1 + 3/4 + 1/2 + 1/4]
= 1/4 [(4 + 3 + 2 + 1)/4] = 5/8 - 1. From a pack of 52 playing cards, two cards are drawn together at random. Calculate the probability of both the cards being king?
Options- A. 1/15
- B. 25/57
- C. 35/256
- D. None of these Discuss
- 2. What is the probability that a non-leap year contains 52 Tuesday only?
Options- A. 1/7
- B. 2/7
- C. 3/7
- D. 6/7 Discuss
- 3. I forgot the last digit of a 7- digit telephone number. If I randomly dial the final 3 digits after correctly dialing the first four, then what is the chance of dialing the correct number?
Options- A. 1/1001
- B. 1/990
- C. 1/999
- D. 1/1000 Discuss
- 4. Three students are picked at random from a school having a total of 1000 students. The probability that these students will have identical date and month of their birth, is?
Options- A. 3/1000
- B. 3/365
- C. 1/(365)2
- D. None of these Discuss
- 5. If E be the set of all integers with 1 in their unit place. The probability that a number chosen {2, 3, 4,...50} is an elements of E, is?
Options- A. 5/49
- B. 4/49
- C. 3/49
- D. 2/49 Discuss
- 6. Raja can hit a target 3 times in 6 shots, Karan can hit the target 2 times in 6 shots and Ashwini can hit 4 times in 4 shots. What is the probability that atleast 2 shots hit the target?
Options- A. 1/2
- B. 2/3
- C. 1/3
- D. 5/6 Discuss
- 7. In his wardrobe, Girdhari has 3 trousers. One of them is grey the second blue and the third brown. In his wardrobe he also has 4 shirts. One of them is grey and the other 3 are white. He opens his wardrobe in the dark and pick out one shirt trouser pair without examination the color. What is the likelihood that neither the shirt nor the trouser is grey?
Options- A. 1/12
- B. 1/6
- C. 1/4
- D. 1/2 Discuss
- 8. 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
- 9. 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
- 10. 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
Probability problems
Search Results
Correct Answer: None of these
Explanation:
Two cards can be drawn from a pack of 52 playing cards in 52C2 ways. i,e., 52 x 51 / 2 = 1326 ways. The event that two kings appear in a single drawn of cards is 4C2 ways, i.e 6 ways.
? The probability that the two cards drawn from a pack of 52 cards are kings = 6/1326 = 1/221
Correct Answer: 6/7
Explanation:
A non-leap year has 365 days, each day repeats for 52 times with 1 day left
This one can be {Sun, Mon, Wed, Thu, Fri, and Sat}.
? p = 6/7
Correct Answer: 1/1000
Explanation:
it is given that last 3 digits are randomly dialed
Then, each of the digit can be selected out of 10 digits in 10 ways. Hence, required probability
= 1/(10)3 = 1/1000
Correct Answer: 1/(365)2
Explanation:
Since, the 1st students can have any day as his birthday and according to the question corresponding to the 1st person and 2nd the 3rd person need to have the same day as their birthday and thus probability that they have identical birthday
= 1x (1/365) x (1/365)
= 1/(365)2
Correct Answer: 4/49
Explanation:
Favourable numbers are 11, 21, 31, 41.
? Required probability = 4/49
Correct Answer: 2/3
Explanation:
Ashwini hits the target definitely, hence required probability that atleast 2 shots hit the target is given by
Karan hits tha target and Raja not hit the target.
or
Karan does not hit the target and Raja hits the target.
or.
Karan hits the target and Raja hits the target
= 2/6 x 3/6 + 4/6 x 3/6 + 2/6 x 3/6
= 24/36 = 2/3
Correct Answer: 1/2
Explanation:
Probability that trouser is not grey = 2/3
Probability that shirt is not grey = 3/4
? Required probability = 2/3 x 3/4 = 1/2
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: 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: 1/8
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
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