Agreen ribbon is 9 inches long. a red ribbon is 1/10 the length of the green ribbon. a purple ribbon is 10 times as long as the red ribbon. what is the length of the purple ribbon?

900 inch
There is 3 ribbon in this question, Red ribbon(R), green ribbon(G) and purple ribbon(P). The relation would be
1. R= 9 inch
2. R= 1/10 G
3. P= 10 G

If you insert equation 1 into 2 then you will get:
9inch= 1/10G
G= 90 inch

After that insert the new equation into equation 3:
P= 10x 90 inch
P= 900inch

J= r + 9 because since jessica rode 9 more miles than roger, you add 9 miles to rogers mileage.