For this case we have a function of the form:
![y = A * (b) ^ x](https://img.qammunity.org/2019/formulas/mathematics/middle-school/njn8jl1tuiqyow3c2397hxw4ywr6fbsp5z.png)
Where,
A: initial amount
b: decrease rate (b <1)
x: independent variable
Y: dependent variable
We observed that,
Intersection with y axis: (0, 60)
Decreasing function (b <1): b=1/3
Answer:
Exponential function that decreases as the domain values increase.