During a flu epidemic, the number of sick people triples every week. What is the growth rate as a percent?

If the growth rate doubled every week, it would grow by 100% per week.

Since the growth rate triples every week, it grows by 200% per week.

This is easy to see.....

If 1 person is sick at the start.......by the end of the first week, 2 more would be sick. And 2 is 200% of 1. So, 3 people are sick at the end of the first week- triple that of the start.

At the end of the second week,  6 more would be sick , and 6 is 200% of 3. So, 9 people total are sick at the end of the second week - triple that of the beginning of the second week.......etc.