Initially, the Product Backlog contained 350 story points of PBIs. After completing 7 sprints of development, the Product Backlog contains 140 story points of PBIs .
The average velocity is 30 per sprint. So it takes 12 sprints to finish the whole project.
After Sprint 9, your client asks to add a new feature. Your team estimates it is 15 story points. Then, after Sprint 10 the client requests another feature to be added. You estimate the size of that feature to be 9 story points. Assuming your team’s velocity does not change, calculate estimates for the total number of sprints.
Scope will continue to increase at the rate of the average of the increases at the ends of Sprints 9 and 10. It will increase at this rate until the Product Backlog is completely burned down during a sprint.
This is where I find difficult. I am not sure how to estimate number of sprints need in this case. What does increase rate is supposed to mean?
Since this is just a estimation, I don't think difficult calculation is needed, does it?
Any help is appreciated.