Answer: 9
Step-by-step explanation: If you need an equation, you can create one:
t = total number of books read
w = weeks
t = 3w
The 3 is there because she reads 3 books weekly, so you multiply the number of weeks by the number of books she reads.
Plug in 3 weeks:
t = 3(3)
t = 9 books
Jessie reads 9 books in 3 weeks.