Wyatt B. answered 06/03/21
ACT Prep, High School Math and Physics Tutor
We're given the distribution of the types of books availabe, so we can determine the total percentage of books that receive favorable reviews and then compare it to the total percentage of books that receive positive reviews that were a huge success or other category.
To do this, we need to multiply each category by the percentage of those books that received positive reviews:
99%*20% + 70%*30% + 40%*40% + 30%*10% = 59.8%
So this tells us the total percentage of books that receive positive reviews. The percentage of books that are hugely successful and receive positive reviews is simply 99%*20%, which is equal to 19.8% of total books.
So since we assume the book has a positive review, it will be a 19.8%/59.8% chance to be a huge success, or 33.11%
The questions in the rest of part A are answered similarily!
For part B, the answer is contained above.