Answer:
Step-by-step explanation:
![S_{31} = 9 \cdot 31 + [-0.5 \cdot \frac{31(31-1)}{2}] = 46.5](https://tex.z-dn.net/?f=S_%7B31%7D%20%3D%209%20%5Ccdot%2031%20%2B%20%5B-0.5%20%5Ccdot%20%5Cfrac%7B31%2831-1%29%7D%7B2%7D%5D%20%3D%2046.5)
![S_{40} = 40 + [-3 \cdot \frac{40(40-1)}{2}] = -2300](https://tex.z-dn.net/?f=S_%7B40%7D%20%3D%2040%20%2B%20%5B-3%20%5Ccdot%20%5Cfrac%7B40%2840-1%29%7D%7B2%7D%5D%20%3D%20-2300)
About 6,000 Double check the answer i gave you.
The starting value is 20,300, and the value is decreasing by 9.5% each year.
Because it decreases by 9.5% each year based on the previous amount, we use an exponential decay model.
A decrease by 9.5% corresponds to multiplying by 91.5% each year.
We write . We plug in 11 years for t.
$7,671.18