Answer: 16 miles per week
Work Shown:
a = change in distance = 492-300 = 192 miles
b = change in time = 12 weeks
c = a/b = rate of change of distance over time = speed of growth
c = (192 miles)/(12 weeks)
c = (192/12) miles per week
c = 16 miles per week
In other words, each time a week goes by, Ryan has walked another 16 miles.
For a related math concept, check out the slope formula. The slope represents the rate of change. It's useful for graphing linear equations.