Chapter 9 - Section 9.4 - Variation and Problem Solving - Exercise Set - Page 664: 40

$108$ cars

Let $C$ be the number of cars manufactured. Let $W$ be the number of workers. Let $t$ be the time the workers work. $C=kWt$ $C=60; W=200; t=2$ $60=k(200)(2)$ $k=\frac{3}{20}$ $C=\frac{3}{20}Wt$ $W=240; t=3$ $W=\frac{3}{20}(240)(3)$ $W=108$ cars