Mathematics
Black-footed ferrets are the only ferret speciesnative to North America, but they were nearlyextinct in the 1970s. Since then, efforts have beenmade to breed the ferrets in captivity andreintroduce them to the wild. The function frepresents the current total population of black-footed ferrets in North America t years after 1991.
f(t)=51.35*1000^(2t/125)
To the nearest year, how many years did (or will) it take for the population to be 10 timeslarger than it was in 1991?
解析：