a2zinterviews

6.	In a box, there are 8 red, 7 blue and 6 green balls. One ball is picked up randomly. What is the probability that it is neither red nor green?
	A.  2/3
	B.  3/4
	C.  7/19
	D.  8/21

Solution

Total number of balls = (8 + 7 + 6) = 21. Let E = event that the ball drawn is neither red nor green =event that the ball drawn is red. Therefore, n(E) = 8. P(E) = 8/21.

7.	The probability that a card drawn from a pack of 52 cards will be a diamond or a king is
	A.  2/13
	B.  4/13
	C.  1/13
	D.  1/52

Solution

Here, n(S) = 52. There are 13 cards of diamond(including 1 king) and there are 3 more kings. Let E = event of getting a diamond or a king. Then, n(E) = (13+3) = 16. Therefore, P(E) = n(E)/n(S) = 16 / 52 = 4 / 13.

8.	In a single throw of a die, what is the probability of getting a number greater than 4?
	A.  1/2
	B.  1/3
	C.  2/3
	D.  1/4

Solution

When a die is thrown, we have S= {1,2,3,4,5,6}. Let E = event of getting a number greater than 4= {5, 6}. •P(E)= n(E) / n(S) = 2/6 = 1/3.

9.	Three unbiased coins are tossed. What is the probability of getting at most two heads?
	A.  3/4
	B.  1/4
	C.  3/8
	D.  7/8

Solution

Here S = {TTT, TTH, THT, HTT, THH, HTH, HHT, HHH} Let E = event of getting at most two heads. Then E = {TTT, TTH, THT, HTT, THH, HTH, HHT}. •P(E)= n(E) / n(S) ‹=›7/8.

10.	A card is drawn from a pack of 52 cards. The probability of getting a queen of club or a king of heart is
	A.  1/13
	B.  2/13
	C.  1/26
	D.  1/52

Solution

Here, n(S) = 52 Let E = event of getting a queen of club or a king of heart. Then, n(E) = 2. P(E) = n(E) / n(S) = 2/52 ‹=›1/26.