Chapter 3 - Polynomial and Rational Functions - 3.6 Variation - 3.6 Exercises - Page 389: 39

$875\ dollars$

Step 1. Assume $I\ (dollars)$ is the simple interest. Step 2. Assume $P\ (dollars)$ is the principal and $t\ (yr)$ is the time. Step 3. From the given conditions, we have $I=kPt$ and $70=k(1000)(2)$, thus $k=\frac{7}{200}$ Step 4. For $P=5000\ (dollars)$ and $t=5\ (yr)$, we have $I=\frac{7}{200}(5000)(5)=875\ dollars$