Answer:
f(t) = 66·0.995^t
Step-by-step explanation:
You can try t=0 and t=1 in each of the formulas to see which one gives values of 66 and 0.5% less than 66, or 65.67.
The first function has an initial value of 0.5, so is not correct.
The second function gives f(1) = 99, so is not correct.
The third function gives f(1) = 65.67, so is correct.
The fourth function gives f(1) = 66.33, so is not correct.
_____
You can realize that the multiplier will be 0.5% less than 100%, so will be 99.5% = 0.995. This number shows up only in the third selection.
