Question

Sam is able to choose from two job positions at one company. He has the option to choose the day shift or the night shift, so it is impossible for Sam to work the day and night shift. If the probability that Sam chooses the day shift is 0.9, and the probability that Sam chooses the night shift is 0.03, what is the probability that Sam chooses the day or night shift?

Answer 1

Let D = Event that Sam chooses Day Shift   N = Event that Sam chooses Night Shift

Given that P(D) = 0.9 and P(N) = 0.03

Now, it is impossible for Sam to work the day and night shift.i.e. P(DN) = 0

We have to find the probability that Sam chooses the day or night shift, i.e. Union of the events D and N

To find : P(D U N)

Using Addition theorem of probability,

  

= 0.93

Hence, the probability that Sam chooses the day or night shift is 0.93.