Probability Tes...

Two boys A and B find the jumble of n ropes lying on the floor. Each takes hold of one loose and randomly. If the probability that they are both holding the same rope is $$\dfrac{1}{101}$$ then the number of ropes is equal to

Counters numbered $$1,2,3$$ are placed in a bag and one is drawn at random and replaced. The operation is being repeated three times. The probabolity of obtaining a total of $$6$$ is ?

Rajdhani Express stops at six intermediate stations between Kota and Mumbai.Five passengers board at Kota. Each passengers can get down at any station till Mumbai. The probability that all five passengers will get down at different stations, is  

If $$A$$ & $$B$$ are two events such that $$P(A)=0.6$$ & $$P(B)=0.8$$, then the greatest value that $$P(A/B)$$ can have is

Of the students in a college, it is known that $$60\%$$ reside in hostel and $$40\%$$ are day scholars (not residing in hostel). Previous year results report that $$30\%$$ of all students who reside in hostel attain A grade and $$20\%$$ of day scholar attain A grade in their annual examination. At the end of the year, one student is chosen at random from the college and he has an A grade, what is the probability that the student is a hostile?

A card is drawn from a deck of cards. What is the probability that it is either a spade or an ace or both 

If two events A and B are such that $$P(A)=0.75\   P(B|A)=0.8\ P(B|A')=0.6$$ Find P(B)

A card is lost from a pack of $$52$$ playing cards. From the remainder of the pack, two cards are drawn and are found to be spade. The probability that the missing card is a spade is :

In a class 5% of boys and 10% of girls have an I.Q of more than 150.In this class 60% of students are boys. If a student is selected at random and found to have an I.Q. of more than 150. Find the probability that the student is a boy.

If $$P(A/B)=P(B/A)$$. $$A$$ and $$B$$ are two non-mutually exclusive events then