This is the question asked?

An exponential function is of the form y = ab^{x}, where a is the initial amount, b is the common growth/decay factor and x is the time or the independent variable.

Look at the equation given, the common decay factor, b, is \frac{2}{3}. In the equation a = 100,000,000 and h is the number of hours.

Look at the graph given,

The points in the graph are (0,250) (1, 150) and so on.

The common growth/decay factor can be found out like dividing \frac{150}{250} = \frac{3}{5}.

So, now compare the fractions \frac{2}{3} and \frac{3}{5} .

Which fraction is smaller? The smaller fraction decays faster.

Here is a similar discussion for you to understand this concept better.

https://www.qalaxia.com/viewDiscussion?messageId=5ef4298b4c60f073ae824e8f

Please get back to me if you have not understood this. You can also post your doubt anonymously. Just saying.