An animal reserve has 40,000 elk. The population increases 11% a year. How long tell the population is equal to 80,000

Initial amount: 40,000

Annual growth rate 11%

Need to reach 80,000 elks in n years:

P=A (1+r) ⁿ

80,000 = 40,000 (1+0.11) ⁿ

80,000 = 40,000 (1.1) ⁿ

Divide both sides by 40,000

2 = (1.1) ⁿ

ln (2) = n. ln (1.1)

0.693147 = n. (0.09531)

and n = 0.693147/0.09531

n = 7.27 years