Answer:
b = 3w; 54
Explanation:
Since the student reads 3 books in one week, we know that one book is three times the amount of weeks, or b = 3w
We can plug in 18 for w to find how many books are read in 18 weeks
b = 3w
b = 3(18)
b = 54
So after 18 weeks she has read 54 books