Distance = Speed × Time
Distance = 35 mph × (30/60) hours
Distance = 17.5 miles
Since there are three stop lights and traffic, we can assume that Darren's average speed will be lower than the speed limit. To compensate for this, we can reduce the average speed by a certain percentage. For example, if we assume that Darren's average speed is 80% of the speed limit, then his average speed would be:
Average speed = 35 mph × 0.8 = 28 mph
Using this average speed, we can calculate the distance Darren can travel in 30 minutes:
Distance = Average speed × Time
Distance = 28 mph × (30/60) hours
Distance = 14 miles
Therefore, Darren can be at work from a distance of about 14 miles.