a. If the value of land in an area is increasing 10.5 percent a year, how long will it take for property values to double? (Round your answer to 1 decimal place.)

6.7 years

Explanation:

This question can be answered using Rule 70. It is a rule that it used to estimate how long it takes for an investment to double in value. In this case, the investment is land and the rate is 10.5%.

Formula for rule 70;

Time it takes for value to double = 70/rate

Time it takes for value to double = 70/10.5

Time = 6.6666

To the nearest 1 decimal place, it would take 6.7 years