The rate of change of a bacteria (N) with respect to time is directly proportional to itself. When t=0, N=500. When t=4, N=3000. How many bacteria will be present when t=8?


Carbon-14 has a half-life of 5715 years. Find the rate of decay, if the initial amount of carbon-14 is 10 units.

Please explain (step by step is preferred)