Speed Distance Time Questions
Speed, distance and time (SDT) questions appear in numerical reasoning tests. They test your ability to use the relationship: Speed = Distance ÷ Time. Here's how to master them.
The Triangle Formula
Speed = Distance ÷ Time. So Distance = Speed × Time and Time = Distance ÷ Speed. Use a triangle: cover the one you need—what's left shows the formula. Example: to find time, cover T; you see D ÷ S.
Unit Conversions
Ensure units match before calculating. If speed is km/h and distance is km, time is in hours. If distance is in metres and speed in m/s, time is in seconds. Convert: 1 km/h = 1000 m ÷ 3600 s ≈ 0.278 m/s.
Average Speed
For a round trip or journey with different speeds, average speed ≠ (speed1 + speed2) ÷ 2. Use: Average speed = Total distance ÷ Total time. Example: 60 km at 60 km/h (1 h) + 60 km at 120 km/h (0.5 h) → total 120 km in 1.5 h → average 80 km/h.
Relative Speed
When two objects move toward each other, add speeds. When moving in the same direction, subtract. Example: trains 80 km apart, speeds 50 km/h and 30 km/h toward each other → relative speed 80 km/h → time to meet = 80 ÷ 80 = 1 hour.
Practice SDT Questions
Build fluency with numerical reasoning practice including the numerical reasoning test, abstract reasoning, and Watson Glaser.
Frequently Asked Questions
How do I handle mixed units (e.g. minutes and hours)?
Convert everything to the same unit first. 1 hour = 60 minutes. Or work in minutes and convert the final answer.
What if the question gives speed in m/s and distance in km?
Convert one to match the other. 1 km = 1000 m. Or convert speed: 1 m/s = 3.6 km/h (multiply by 18/5).
Are SDT questions common in all aptitude tests?
More common in numerical reasoning. They reinforce ratio and proportion skills—speed is effectively distance per unit time.