SOLUTION: hellllp please A population of 10,000 citizens in a coastal North Carolina town is increasing its numbers by approximately 4% each year. Once the population reaches 20,000, they

Algebra ->  Finance -> SOLUTION: hellllp please A population of 10,000 citizens in a coastal North Carolina town is increasing its numbers by approximately 4% each year. Once the population reaches 20,000, they      Log On


   

Question 891612: hellllp please
A population of 10,000 citizens in a coastal North Carolina town is increasing its numbers by approximately 4% each year. Once the population reaches 20,000, they will be eligible for digital traffic lights in the center of town. In approximately how many years will it take the town to get digital traffic signals at this rate?

17.7 years

17.2 years

18.1 years

20 years
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
highlight_green%2810000%2A1.04%5Et=20000%29, exponential growth, time t in years.

1%2A1.04%5Et=2
1.04%5Et=2
log%2810%2C%281.04%5Et%29%29=log%2810%2C2%29
t%2Alog%2810%2C1.04%29=log%2810%2C2%29
highlight%28t=log%2810%2C2%29%2Flog%2810%2C1.04%29%29

You'll just need to evaluate that numeric expression.