Problem 4-21 Growth Rates Sales for Hanebury Corporation's just-ended year were $6 million. Sales were $3 million 5 years earlier.

At what rate did sales grow? Round your answer to the nearest whole number.

Suppose someone calculated the sales growth for Hanebury Corporation in part a as follows: "Sales doubled in 5 years. This represents a growth of 100% in 5 years; dividing 100% by 5, we find the growth rate to be 20% per year." Explain what is wrong with this calculation.