West African Elephants There were once more than $1 \mathrm{mil}-$ lion elephants in West Africa. Now, however, the elephant population has dwindled to $19,000 .$ Each year, $17.8 \%$ of West Africa elephants die or are killed by hunters. At the same time, elephant births are decreasing by $13 \%$ per year. (Source: Douglas Chadwick, The Fate of the Elephant, San Francisco: Sierra Club Books, 1992 )
a. How many of the current population of 19,000 elephants will still be alive 30 years from now?
b. Considering that 47 elephants were born in the wild this year, write a model for the number of elephants that will be born $t$ years from now and will still be alive 30 years from now.
c. Calculate the elephant population of West Africa 30 years from now.