Evolution of Language: The number of years, n, since two independently evolving languages split off from a common ancestral language is approximated by
n=-7600 log r,
where r is the proportion of words from the ancestral language common to both langages.
(a) Find n if r=.9. (b) Find n if r=.3
(c) How many years have elasped since the spilt if half of the words of the ancestral language are common to both languages?