If you are just dividing percent's, then each grade would have 12.5 percent.
Jim is correct because the ratios need to compare with the total amount of people surveyed. 55, 80, and 65 are numbers that don't fit in and don't tell the overall ratio. You can tell this by writing it as a fraction.
Ex: 35:100 = 35/100. This literally means 35 out of 100 people exercise in the morning.
Hope this helps! If you have any questions, just ask!
Y=Mx+b (m is slope, b is y-intercept)
