- #1

royalewithchz

- 7

- 0

## Homework Statement

Three people work independently at deciphering a message sent in code. the respective probabilities are

persion a: 1/6

person b: 1/8

person c: 2/7

what is the probability that the message will be decoded

## Homework Equations

(A or B ) = Pr(A) + Pr(b) - Pr(A and B)

A' = 1 - A

## The Attempt at a Solution

My first solution was:

decoded message = Pr(A) + Pr(b) + Pr(C) - ( Pr(A)Pr(b)Pr(c) + Pr(A)Pr(B) + Pr(A)Pr(c) + Pr(B)Pr(c))

and I thought it made sense, apparently the answer is not the same. The actual answer is taking the inverse

decoded = ( 1 - Pr(A) ) + ( 1 - Pr(B) ) + ( 1 - Pr(C) )

I understand this method, But I was curious why doesn't my method work?