Final answer:
Without the specific rate at which books are sold, it's impossible to accurately determine the number of books sold in 3 weeks. An example is provided assuming a hypothetical rate.
Step-by-step explanation:
The question does not provide enough specific information about the rate at which books are sold, which is necessary to calculate the total number of books sold in 3 weeks. To make this calculation, we would need to know the number of books sold per week or have some kind of data indicating the sales trend over time.
However, if we consider the given rates from similar questions provided in the information, like the number of cars sold by car salespersons, we can assume that the rate would be stable each week for books sold. If we were given a stable rate, say 70 books per week, then over 3 weeks, the total number of books sold would be 70 books/week x 3 weeks = 210 books. Without the specific rate, we cannot definitively answer the student’s question.