Answer
15.4 years
Work Step by Step
Growth rate of .4%, starting population of 65,822,000
Goal population of 70,000,000
$70000000=65822000*1.004^x$
$70000000/65822000 = 65822000*1.004^x/65822000$
$1.06347 =1.004^x$
$ln 1.06357 = x*ln 1.004$
$ln 1.06357/ln 1.004 = x*ln 1.004/ln 1.004$
$ ln 1.06357/ln 1.004 = x$
$15.41 =x$
