The formula for percentage increase is the increase in the original value. Between last year and this year, there was an increase of 9 science projects, so the increase = 9. The original number of science projects = 43.
9 divided by 43 = 0.2093, about. Multiply it by 100 to get it as a percentage: 20.93%
Since the problem requests it rounded to the nearest tenth, the percent change in the number of projects submitted is 20.9%.
