THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION

Essay

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A company wishes to evaluate the effectiveness of a marketing campaign.Seventy five percent of all potential professors were reached in a focused advertising program.Twenty eight percent of those contacted adopted the book while 8% of the adoptions came from professors who did not receive the promotional material.Define the following events of interest:
A₁ = Professor received advertising material
A₂ = Professor did not receive advertising material
B₁ = Professor adopts the book
B₂ = Professor does not adopt the book
-What is the probability that a professor who adopts the book has not received the advertising material?