A tree initially measured 18 ft tall. Over the next 3 1/2 years, it grew to a final height of 35 1/2 feet. During those 3 1 /2 years, what was the average yearly growth rate of the height of the tree?
The tree grew 35.5 - 18 ft = 17.5 feet in 3.5 years this averages to 17.5 ft / 3.5 yr = 5 ft/yr