Fill in the blanks:
The probability of a sure event is .......
Two aeroplanes I and II bomb a target in succession. The probabilities of I and II scoring a hit correctly are 0.3 and 0.2, respectively. The second plane will bomb only if the first misses the target. The probability that the target is hit by the second plane is
In a case, 40% students study mathematics; 25% study biology and 15% study both mathematics and biology. One student is selected at random.
Find the probability that he studies biology if it is known that he studies mathematics.
Three persons A, B and C apply for a job of Manager in a Private Company. Chances of their selection (A, B and C) are in the ratio 1 : 2 : 4. The probabilities that A, B and C can introduce changes to improve profits of the company are 0.8, 0.5 and 0.3 respectively. If the change does not take place, find the probability that it is due to the appointment of C.
Probabilities of solving a specific problem independently by A and B are21 and31respectively. If both try to solve the problem independently, find the probability that (i) the problem is solved (ii) exactly one of them solves the problem.
A pair of dice is thrown 4 times. If getting a doublet is considered a success, find the probability distribution of number of successes.
four fair dice D1,D2,D3andD4 each having six faces numbered 1,2,3,4,5 and 6 are rolled simultaneously. The probability that D4 shows a number appearing on one of D1,D2,D3 is
In a hostel 60% of the students read Hindi newspaper, 40% read English newspaper and 20% read Hindi and English newspapers. A student is selected at random.
If he reads English newspaper, what is the probability that he reads Hindi newspaper ?