Final answer:
Without knowing the speeds of Salim's and Jia's model cars, we cannot determine the relative distance by which Salim's car is ahead of Jia's car after 3 seconds.
Step-by-step explanation:
The question pertains to the relative distances covered by two model cars, Salim's and Jia's, traveling at constant speeds over a period of 3 seconds. To determine how far ahead Salim's car is as compared to Jia's car after 3 seconds, we would need to know the speed of both model cars, which is not provided in the question. Because key information is missing (the speeds of Salim's and Jia's cars), it's impossible to accurately calculate the distances without making assumptions. Therefore, we cannot determine whether the distance is the same, twice, three times, or four times ahead.