#### Answer

$124\ ft$

#### Work Step by Step

Step 1. Based on the given table, we can find $\lim_{x\to60}f(x)=124\ ft$, which means that at a speed of $60\ mi/h$, you should keep a distance of $124\ ft$ from the car in front of you.
Step 2. We evaluate $f(60)=0.015(60)^2+(60)+10=124\ ft$, which agrees with the limit obtained above.