word problem: population growth

[kellyanne]

I'm really new at this whole message board thing.. but I'll give it a try.
I have summer work to do which is reviewing from last year (Math Analysis Honors).. it was a bad idea to throw away all my notes from last year because I don't remember anything. AP calc is going to be a long year this year.. oh joy.

The problem is:

The population of Silver Run in the year 1890 was 6250. Assume the population increased at a rate of 2.75% per year. (a) Estimate the population in 1915 and (b) approximate when the population is 50,000.

I would appreciate the help

 

[stapel]

The population of Silver Run in the year 1890 was 6250. Assume the population increased at a rate of 2.75% per year. (a) Estimate the population in 1915 and (b) approximate when the population is 50,000.

I would expect you're supposed to use the compound-interest (compounded growth) formula:

. . . . .A = P(1 + r/n)^nt

...where "A" is the ending amount, "P" is the beginning amount, "r" is the compound growth rate per some time period (here, years), "n" is the number of compoundings per interest period (here, years), and "t" is the number of time periods (again, years).

Let "t = 0" stand for 1890, and P = 6250. Then plug-n-chug.

Eliz.