Let c(t) be the level of C14 at time t. Then where is the level at t = 0 and k is some constant.

(1) Find k from the fact that (5,730 years is the half-life of carbon-14).

(2) Find , which is the percentage of C14 lost between 12300BC and 2000AD.

(3) Find , which is the percentage of C14 lost between 13000BC and 2000AD.

(4) Find the difference between (3) and (2).