One molecule of glucose makes 30 molecules of ATP.
Therefore, 200 glucose molecules will be yielding 6000 molecules of ATP.
We ca n calculate by the following way,
1glucose / 30 molecules of ATP or 30 molecules of ATP / 1 glucose
According to this we can figure out the total number of glucose molecules to yield 6000 ATP's.
6000 molecules of ATP / 1 * 1 glucose / 30 molecules of ATP.
Which is 200 glucose molecules.