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.

Chris says substitute r=.9 into the equation and evaluate
(b) Find n if r=.3

Chris says substitute r=.3 into the equation and evaluate
(c) How many years have elasped since the spilt if half of the words of the ancestral language are common to both languages?

Chris says that r is given to us: r=.5. Now evaluate