Sarthaks APP
0 votes
3.4k views
in Mathematics by (8.0k points)
A lot consists of 144 ball pens of which 20 are defective and others good. Nun will buy a pen if it is good, but will not buy if it is defective. The shopkeeper draws one pen at random and gives it to her. What is the probability that

(i) She will buy it?

(ii) She will not buy it?

1 Answer

0 votes
by (13.1k points)
selected by
 
Best answer

No. of good pens = 144 – 20 = 24

No. of detective pens = 20

Total no. of possible outcomes = 144 {total no pens}

(i) E ⟶ event of buying pen which is good.

No. of favourable outcomes = 124 {124 good pens}

P(E) = (No.of favorable outcomes)/(Total no.of possible outcomes)

P(E) = 124/144 = 31/36

(ii) Bar  E⟶ event of not buying a pen which is bad P(E) + P(Bar E) = 1

P(E)+P(Bar E)=1

P(Bar E) = 1 - P(E)

=1−31/36 = 5/36

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...