Question

The probability a getting a job is 1/5 and that of b is 1/7 . what is the probability that only one of them gets a job?

Answer 1

Hi ,

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For any event E ,

P( E ) + P ( E )' = 1

Where E' stands for ' not E .

E and E' are called Complementary

events .

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i ) The probability of getting A job 1/5

Probability of A not getting job

P( A' )= 1 - 1/5 = 4/5

ii ) probability of B getting a job = 1/7

Probability of B not getting job

= 1 - 1/7

P( B ' )= 6/7

Now , probability of only one of them

getting a job

= P( A ) × P( B' ) + P ( A' ) × P( B )

= ( 1/5 ) ( 6/7 ) + ( 4/5 ) × ( 1/7 )

= 6/35 + 4/35

= ( 6 + 4 )/35

= 10/35

= 2/7

I hope this helps you.

: )