An atmospheric scientist monitors the concentration of a synthetic coolant gas, $C$ parts per trillion (ppt), in the stratosphere. The scientist believes the concentration has been growing exponentially since the start of 2005 and proposes the model

$$C=p\times q^n$$

where $n$ is the number of years after 2005, and $p$ and $q$ are constants.

A graph of ${\log }_{10}C$ against $n$ is plotted, and the resulting line of best fit has the equation:

$${\log }_{10}C=0.052n+0.86$$