Suga,
It will depend upon which version of BOE you are on. I'll presume 3.1.
What you are looking for is a shceudle-based event. In a schedule-based event, the completion of one schedule triggers another. The schedules of both reports must include this event: one with the event as an event to trigger, the other with the event as an event to wait for.
You need to first create the event, then make it a part of your schedules.
Creating a Schedule-Based Event
From the “New Event” window:
1. Select “Schedule” for the event type
2. Enter the event name
3. Enter a description if desired.
4. Select the event status option you want, “Success or Failure”?
5. Select “OK”
6. Right-click on the new event – select User Security
7. Add your user group with the access level you want
Add the event to your report schedules:
For the first report, add the event as an event to trigger (at the bottom).
For the second report, add the event as an event to wait for.
You would then need to have a different event to start report three. You'd place the second event in the second reports "Event to trigger, and so on, so that means you would have 49 events. But you don't need to. There are other ways to go about it, such as triggering more than one report at a time or working with your schedule time windows.
You might also look into objects packages. If you place, say, 5 reports in a package you can schedule the packages to run consequetively.