Answer:
5 hours
Explanation:
Since Shen drove at the same rate for both distances, we can use a proportion to solve for the time it would take him to drive 335 miles:

where d1 is 603 miles, t1 is 9 hours, d2 is 335, and t2 is the unknown value.
Thus, we can simply plug in everything to the equation and solve for t2:

(*Note that 9 divides evenly into 603 and becomes 67, which is why I didn't cross-multiply first with he 603 and t2 and the 335 and 9, although you'd still get the same result for t2)
Thus, it would take Shen 5 hours to drive 335 miles.
You can check by finding the rate for both equations since we know that distance is equal to the product of rate and time (d = rt):
First equation: 603 miles = 9 hours * r mph
67 mph = r
603 = 67 * 9
Second equation: 335 miles = 5 hr * r mph
67 mph = r
335 = 67 * 5