Answer:
2019.
Step-by-step explanation:
We have been given that for the years from 2002 and projected to 2024, the national health care expenditures H, in billions of dollars, can be modeled by
where t is the number of years past 2000.
To find the year in which national health care expenditures expected to reach $4.0 trillion (that is, $4,000 billion), we will substitute
in our given formula and solve for t as:
![4,000= 1,500e^{0.053t}](https://tex.z-dn.net/?f=4%2C000%3D%201%2C500e%5E%7B0.053t%7D)
![\frac{4,000}{1,500}=\frac{ 1,500e^{0.053t}}{1,500}](https://tex.z-dn.net/?f=%5Cfrac%7B4%2C000%7D%7B1%2C500%7D%3D%5Cfrac%7B%201%2C500e%5E%7B0.053t%7D%7D%7B1%2C500%7D)
![\frac{8}{3}=e^{0.053t}](https://tex.z-dn.net/?f=%5Cfrac%7B8%7D%7B3%7D%3De%5E%7B0.053t%7D)
![e^{0.053t}=\frac{8}{3}](https://tex.z-dn.net/?f=e%5E%7B0.053t%7D%3D%5Cfrac%7B8%7D%7B3%7D)
Take natural log of both sides:
![\text{ln}(e^{0.053t})=\text{ln}(\frac{8}{3})](https://tex.z-dn.net/?f=%5Ctext%7Bln%7D%28e%5E%7B0.053t%7D%29%3D%5Ctext%7Bln%7D%28%5Cfrac%7B8%7D%7B3%7D%29)
![0.053t\cdot \text{ln}(e)=\text{ln}(\frac{8}{3})](https://tex.z-dn.net/?f=0.053t%5Ccdot%20%5Ctext%7Bln%7D%28e%29%3D%5Ctext%7Bln%7D%28%5Cfrac%7B8%7D%7B3%7D%29)
![0.053t\cdot (1)=0.9808292530117262](https://tex.z-dn.net/?f=0.053t%5Ccdot%20%281%29%3D0.9808292530117262)
![\frac{0.053t}{0.053}=\frac{0.9808292530117262}{0.053}](https://tex.z-dn.net/?f=%5Cfrac%7B0.053t%7D%7B0.053%7D%3D%5Cfrac%7B0.9808292530117262%7D%7B0.053%7D)
![t=18.506212320](https://tex.z-dn.net/?f=t%3D18.506212320)
So in the 18.5 years after 2000 the expenditure will reach 4 trillion.
![2000+18.5=2018.5](https://tex.z-dn.net/?f=2000%2B18.5%3D2018.5)
Therefore, in year 2019 national health care expenditures are expected to reach $4.0 trillion.