Bob bought some land costing $15,390. Today, that same land is valued at $44,817. How long has Bob owned this land if the price of land has been increasing at 5 percent per year?

Bob bought the land 21 years and 332 days ago.

Explanation:

Giving the following information:

Bob bought some land costing $15,390. Today, that same land is valued at $44,817.

To calculate the number of years passed we need to use a variation of the Future Value formula:

FV=PV * (1+i) ^n

Isolating n:

n=[ln (FV/PV) ]/ln (1+i)

n = [ln (44,817/15,390) / ln (1.05) ]

n = 21.91

0.91*365 = 332

Bob bought the land 21 years and 332 days ago.