After 7 weeks, Mia's office will have recycled 21 pounds.
Step-by-step explanation:
With the information provided, you can use a rule of three to find the pounds of paper that Mia's office will have recycled after 7 weeks given that they recycled 9 pounds over 3 weeks.
3 weeks → 9 pounds
7 weeks → x
x=(7*9)/3
x=21
According this, the answer is that after 7 weeks, Mia's office will have recycled 21 pounds.