You are driving in urban traffic on a dry roadway in a stream of traffic travelling at a speed of 50 km/h. What is the minimum safe distance you must keep from the vehicle in front?

At 50 km/h in a built-up area, the rule of thumb for a minimum safe following distance is “half the speedometer reading in meters.” Half of 50 is 25, so you should keep at least about 25 meters behind the vehicle in front. That gives you enough space to react and brake if the vehicle ahead suddenly slows or stops.

Answer 1 is the only one that fits this principle. 15 m is already closer than the rule-of-thumb minimum, but among the given choices it is the largest distance and therefore the safest minimum offered. Answers 2 (10 m) and 3 (5 m) are far too short at 50 km/h and would not allow enough reaction and braking distance in normal urban driving.

To solve similar questions: take your speed in km/h, divide by 2, and that number in meters is the minimum following distance in good conditions. If it’s wet, icy, or visibility is poor, increase it (often roughly double in rain).