Q1. In a bag there are 2 blue balls, 5 white balls and 3 red balls. 2 balls are drawn one by one without replacement. If the first ball comes out to be of red colour, then 5 more red coloured balls are added to bag. Find the probability that none of the balls drawn are of red colour ?
a) 13/20
b) 17/20
c) 19/20
d) 11/20
e) None of these

Q2. What is the probability of getting a number not greater than 4 when a dice is rolled?
a) Â½
b) 1/6
c) 2/3
d) Â¼

Q3. A pack contains 4 blue, 2 red and 3 black pens. If 2 pens are drawn at random from the pack, NOT replaced and then another pen is drawn. What is the probability of drawing 2 blue pens and 1 black pen?
a) 2/7
b) 1/14
c) 2/18
d) 3/19

Q4. A box contains 4 chocobars and 4 ice creams. Tom eats 3 of them, by randomly choosing. What is the probability of choosing 2 chocobars and 1 icecream?
a) 1/7
b) 2/9
c) 3/18
d) 4/7

Q5. In a class, there are 12 boys and 16 girls. One of them is called out by an enroll number, what is the probability that the one called is a girl?
a) 1/4
b) 2/5
c) 5/12
d) 4/7

Q6. A family has two children. find the probability that both the children are girls given that at least one of them is a girl?
a) Â¼
b) 2/3
c) 1/3
d) Â¼

Q7. Ten cards numbered 1 to 10 are placed in a box, mixed up thoroughly and then one card is drawn randomly. If it is known that the number on the drawn card is more than 3, what is the probability that it is an even number?
a) 2/7
b) 6/7
c) 7/2
d) 4/7

Q8. A die is thrown three times. Events X and Y are defined as below:
X : 4 on the third throw
Y : 6 on the first and 5 on the second throw
What is the probability of X given that Y has already occurred.
a) 2/6
b) 1/6
c) 1/5
d) None of these

Q9. A die is thrown twice and the sum of the numbers appearing is observed to be 6. find the conditional probability that the number 4 has appeared at least once?
a) 1/5
b) 3/5
c) 2/5
d) None of these

Q10. Given that E and F are events such that P(E) = 0.16, P(F) = 0.4 and P(E n F) = 0.4,
find P (E|F) and P(F|E)
a) 3/4, 2
b) 1/4 , 1
c) 1, 1/4
d) None of these

Solution