Someone said : “I want all of this by that date”
This type of project is generally considered the hardest to manage.
There are two type of this kind of project.
1. You are given no choice. This refers to the cases when someone has literally dictated both date and scope. First assess the risk trying to do everything by the given date. Next decide to do the project or not
2. Second type of this project is when you have some flexibilty. Again start by assessing the risk. And then try to balance the scope and schedule risk equally.
You can calculate easily the values above. Check "Simple Release Planning with Historical Velocity Data" post to see how you can find the velocity range.
So at this point you should discuss and choice a scope-based option “200 points in 11 iterations” or a date-based option “180 points in 10 iterations”.