In order to travel 230 miles in 4 hours, the car would need to have a rate of
(230 mi)/(4 h) = 57.5 mi/h
If the car travels at 65 mi/h, the trip will take less than 4 hours, so the car will reach Oceanside within the required time.
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The speed limit for Oceanside is irrelevant, because the car is not IN Oceanside. It is traveling TO Oceanside. The speed limit along the path of travel is not specified here. Details are important in math (and in speed law enforcement).