Answer
9.4 years
Work Step by Step
2009 population is 62.6 million
growth of 0.4% per year
goal of 65 million
$65000000=62600000*(1+.004)^x$
$65000000/62600000=62600000*(1+.004)^x/62600000$
$650/626=(1+.004)^x$
$1.038338=(1+.004)^x$
$log {1.038338} = log {(1+.004)^x}$
$log {1.038338} = x log {1.004}$
$log {1.038338}/log {1.004} = x log {1.004}/log {1.004}$
$log {1.038338}/log {1.004} = x$
$.0163387/.0017337 =x$
$9.4 =x$
