Answer: Linear model
and H'(t) = 9 units.
Explanation:
Since we have given that
In 2000, amount spent = $100 billions
In 2010, amount spent = $190 billions.
So, rate of increase would be
![(190-100)/(2010-2000)\\\\=(90)/(10)\\\\=9](https://img.qammunity.org/2020/formulas/mathematics/college/mfskg13n8n3snbewm6fa2h478pbmybrwb7.png)
So, linear model for H(t) would be
![H(t)-190=9(t-10)\\\\H(t)=9t-90+190\\\\H(t)=9t+100](https://img.qammunity.org/2020/formulas/mathematics/college/jnjx2sq825g13tv5x5wpnbknvp1yf113sd.png)
So, H'(t) would be 9.
Hence, linear model
and H'(t) = 9 units.