general equation is
solve for k.
use the equation and the value of k found above ...
and solve for t to find the half-life
A sample of 100g (intially) of pure Bismuth-210 contains only 14.4 g of the radioactive substance after 14 days. Determine the mass m(t) of bismuth-210 after t days and the half-life of bismuth-210.
Any help will be much appreciated! thanx