To write a direct variation equation for the number of miles a jet travels, you can use the formula:
\[ y = kx \]
where \( y \) is the distance traveled, \( k \) is the rate (in this case, 600 mph), and \( x \) is the time in hours.
So, for a jet flying at 600 mph, the equation would be:
\[ y = 600x \]
Now, if you want to find the distance the jet travels in 3 hours, substitute \( x = 3 \):
\[ y = 600 \cdot 3 \]
Therefore, the correct response from your options that closely matches this equation is:
y = 600x3