My question is:

A company wishes to evaluate the effectiveness of a marketing campaign.
Seventy-five percent of all customers using the product were reached in a
focused advertising campaign. Twenty-eight percent of those reached through
the campaign purchased the product while 8% of the purchases came from
customers who did not receive the targeted advertising campaign. Answer the
following questions:

What is the probability a professor who adopts a book received the advertising material?

I've been told the answer is 0.91 but cant seem to get to it 😭😭😭😭

Thanks in advance for any help!!! 🙌🙌