PROBABILITY

Question

HOW TO DECIDE OR CHECK??

Comments

WHAT IS THE ANSWER?

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I don't know

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P(AUB)+P(A INTER B)=1.1 . OPTION C LOOK CLOSE TO ME

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adarsh_1997 HOW ? CAN U EXPLAIN?

Answer 1

Given p(A)=0.3 p(B)=0.8

P(AUB)=P(A)+P(B)-P(AnB)

As sum of P(A) and P(B) is greater than one so it's clear P(AnB) !=0 and also P(AUB)<=1  --1

P(A) +P(B)=1.1

so minimum value of P(AnB)=0.1 --to get the maximum value of P(AuB)=1

And maximum value of P(AnB) will be when either of A or B is subset of other as P(A)<P(B) so A is subset of B thus P(AnB)=0.3 (maximum value)

Using this maximum value we will get the minimum value of P(AuB)=0.8

So option a is correct.

Comments

Soumya Tiwari 

As sum of P(A) and P(B) is greater than one so it's clear P(AnB) !=0 and also P(AUB)=1  --1
 

 P(AUB)=1  SHOULD BE P(AUB)<=1 ??

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Yes thanks made changes :)

Answer 2

I think A should be the answer because ATQ

 n(AUB) =1.1-n(A intersection B)

if n(A intersection B)=0.3

then n(AUB)=0.8

and this only follows in option A.