Question 1141088
p(A or B) = p(A) + p(B) - p(A and B)


A equals number of weeks where overtime was paid.


B equals number of weeks where temporary help was hired.


formula becomes p(A or B) = 18/52 + 9/52 - 5/52.


solve for p(A or B) to get p(A or B) = 22/52.


another way to look at it is as follows:


take out the number of weeks where overtime and temporary help were involved from each of the categories.


you will get.


overtime weeks only equal 18 - 5 = 13
temporary help weeks only equal 9 - 5 = 4
overtime and temporary help weeks equal 5
total weeks = 52


probability of randomly selectng a week where either overtime was involved or temporary help was involved or both were involved would be:


(13 + 4 + 5) / 52 = 22/52.