Answer:
Step-by-step explanation:
This is a geometric sequence of the form [tex]F=Ir^t\text{ where I=initial value, r=common ratio, and t=number of terms or time. Notice each term is 1/4 of the preceding term. This is the common ratio. So your equation is }f(x)=40\left(\frac{1}{4}\right)^x[/tex]
