To find the number of miles a jet travels in a given amount of time when it is flying at a constant speed, we can use the direct variation equation of the form \( y = kx \), where:
- \( y \) is the distance traveled (in miles),
- \( k \) is the rate of speed (in miles per hour),
- \( x \) is the time (in hours).
In this case, the rate of speed \( k \) is 600 mph, and the time \( x \) is 3 hours.
The direct variation equation can be set up as:
\[ y = 600x \]
Now, we can substitute \( x = 3 \) hours into the equation to find \( y \):
\[ y = 600 \times 3 \]
\[ y = 1800 \]
Thus, the jet travels 1,800 miles in 3 hours.