148 questions asked across 20 exam years, newest first
A candidate has to go to the examination centre to appear in an examination. The candidate uses only one means of transportation for the entire distance out of bus, scooter and car. The probabilities of the candidate going by bus, scooter and car, respectively, are , and . The probabilities that the candidate reaches late at the examination centre are , and if the candidate uses bus, scooter and car, respectively. Given that the candidate reached late at the examination centre, the probability that the candidate travelled by bus is :
Answer: B
A bag contains coins N fair coins, and one coin with 'Head' on both sides. A coin is selected at random and tossed. If the probability of getting 'Head' is , then N is equal to:
Answer: B
A bag contains 6 blue and 6 green balls. Pairs of balls are drawn without replacement until the bag is empty. The probability that each drawn pair consists of one blue and one green ball is :
Answer: C
A letter is known to have arrived by post either from KANPUR or from ANANTPUR. On the envelope just two consecutive letters AN are visible. The probability, that the letter came from ANANTPUR, is:
Answer: B
The probabilities that players A and B of a team are selected for the captaincy for a tournament are and , respectively. If A is selected the captain, the probability that the team wins the tournament is and if B is selected the captain, the probability that the team wins the tournament is . Then the probability, that the team wins the tournament, is :
Answer: B
A coin is tossed 8 times. If the probability that exactly 4 heads appear in the first six tosses and exactly 3 heads appear in the last five tosses is , then is equal to _________.
Answer: 9
From a month of 31 days, 3 different dates are selected at random. If the probability that these dates are in an increasing A.P. is equal to , where and , then is equal to ____.
Answer: 944
One mole of an alkane (x) requires 8 mole oxygen for complete combustion. Sum of number of carbon and hydrogen atoms in the alkane (x) is ________.
Answer: 81
A man throws a fair coin repeatedly. He gets 10 points for each head he throws and 5 points for each tail he throws. If the probability that he gets exactly 30 points is , , then is equal to :
Answer: C
A bag contains balls out of which are red and are black, where . If three balls are drawn at random without replacement and all of them are found to be black, then the probability that the bag contains red and black balls is:
Answer: D
The probability distribution of a random variable X is given below : If , then is equal to :
Answer: D
From a lot containing 10 defective and 90 non-defective bulbs, 8 bulbs are selected one by one with replacement. Then the probability of getting at least 7 defective bulbs is
Answer: A
From the first 100 natural numbers, two numbers first and then are selected randomly without replacement. If the probability that is , , then is equal to ____ .
Answer: 311
Bag A contains 9 white and 8 black balls, while bag B contains 6 white and 4 black balls. One ball is randomly picked up from the bag B and mixed up with the balls in the bag A . Then a ball is randomly drawn from the bag A . If the probability, that the ball drawn is white, is , , then is equal to
Answer: C
Two distinct numbers and are selected at random from . The probability, that their product is divisible by 3 , is
Answer: C
If a random variable has the probability distribution then is equal to
Answer: D