CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

A box has 50 pens of which 20 are defective. What is the probability that out of a sample of 5 pens drawn one by one with replacement, at most one is defective?


Your Answer
A
3.6×(35)4
Your Answer
B
(35)5
Correct Answer
C
2.6×(35)4
Your Answer
D
(25)5

Solution

The correct option is D 2.6×(35)4
Clearly, number of defective pens is a random variable.Let it be denoted by X.Let p denote the probability of getting a defective pen.Then, p=2050=25   and q=125=35For  selecting at most one defective pen, we have two conditions, either no pen is defective or only one pen is defective.The problem is a binomial experiment, withn=5, p=25 and q=35.Therefore, probability of getting at most one defective pen is P(X=0) + P(X=1).or,    5C0(25)0×(35)5+ 5C1(25)1×(35)4or,    1×1×(35)5+5×25×(35)4or,    (35)4(35+2)or,    (35)4(135)or,    2.6×(35)4
 

flag
 Suggest corrections
thumbs-up
 
0 Upvotes


Similar questions
View More


People also searched for
View More



footer-image