# Exponential and logarithmic functions in carbon 14 dating

When an organism dies it ceases to replenish carbon in its tissues and the decay of carbon 14 to nitrogen 14 changes the ratio of carbon 12 to carbon 14.

Experts can compare the ratio of carbon 12 to carbon 14 in dead material to the ratio when the organism was alive to estimate the date of its death.

With situations involving decay, the rate of growth is always negative.

The half-life of a substance is the amount of time it takes for half of that substance to decay.

The kerosene is purified by removing pollutants, using a clay filter.

This means that it has a constant relative rate of decay.

The same equation is used for this situation as for continuous compounding and population growth.

How long does the pipe have to be to ensure that there is only 10% of the pollutants left in the kerosene?

This means that we need a pipe that is 10.3 feet long in order for the pollutants to be reduced to 10% of their starting amount.