Download Aptitude Crack
img not found img not found

Probability

Q1: A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is:

A
1
22

B
3
22

C
2
91

D
2
77

ANS:C -

2
91

Let S be the sample space.

Then, n(S) = number of ways of drawing 3 balls out of 15
= 15C3
= (15 x 14 x 13)
(3 x 2 x 1)
= 455.
Let E = event of getting all the 3 red balls.
n(E) = 5C3 = 5C2 = (5 x 4) = 10.
(2 x 1)
P(E) = n(E) = 10 = 2 .
n(S) 455 91



img not found
img

For help Students Orientation
Mcqs Questions

One stop destination for examination, preparation, recruitment, and more. Specially designed online test to solve all your preparation worries. Go wherever you want to and practice whenever you want, using the online test platform.