Speed, Time and Distance
⚡ Unlock time-saving calculation tricks and mental math techniques. Solve complex problems in seconds with proven shortcut methods used by top performers.
Shortcut Techniques
Study MaterialShortcut Techniques – Speed, Time and Distance
Shortcut techniques in Speed, Time and Distance help candidates solve aptitude questions quickly and accurately in SSC, Banking, Railway, CDS, NDA, CAT, UPSC, Defence, and placement examinations.
Most questions from this chapter involve:
- Basic speed calculations
- Average speed
- Relative speed
- Train problems
- Boats and streams
- Race problems
- Circular track concepts
Using shortcut techniques reduces lengthy calculations and improves solving speed significantly.
Why Learn Speed, Time and Distance Shortcuts?
- Improves calculation speed in exams.
- Reduces lengthy mathematical calculations.
- Useful in trains and boats problems.
- Improves analytical thinking.
- Helps solve complex problems quickly.
Shortcut #1: Formula Triangle Technique
Memorize the relationship:
Distance
Speed × Time
Using this:
- Speed = Distance / Time
- Time = Distance / Speed
- Distance = Speed × Time
✔ This eliminates confusion during exams.
Shortcut #2: km/h to m/s Conversion Trick
To convert km/h into m/s:
Multiply by 5/18
Example:
72 km/h:
= 72 × 5/18
= 20 m/s
Shortcut #3: m/s to km/h Conversion Trick
To convert m/s into km/h:
Multiply by 18/5
Example:
25 m/s:
= 25 × 18/5
= 90 km/h
Shortcut #4: Relative Speed Technique
Same Direction
Relative Speed = Difference of Speeds
Opposite Direction
Relative Speed = Sum of Speeds
Shortcut #5: Speed Ratio and Time Ratio
For the same distance:
Speed Ratio = Inverse of Time Ratio
Example:
Speed ratio:
= 3 : 4
Time ratio:
= 4 : 3
Shortcut #6: Average Speed for Equal Distances
If equal distances are travelled at speeds x and y:
Average Speed = 2xy / (x + y)
Example:
60 km/h and 40 km/h
Average speed:
= (2 × 60 × 40)/(60 + 40)
= 48 km/h
✔ Do not use arithmetic mean for equal distance problems.
Shortcut #7: Train Crossing Pole Trick
When a train crosses a pole:
Time = Length of Train / Speed
Only train length is considered.
Shortcut #8: Train Crossing Platform Trick
When a train crosses a platform:
Time = (Train Length + Platform Length) / Speed
Shortcut #9: Two Trains Crossing
When two trains move in opposite directions:
Time = Sum of Lengths / Sum of Speeds
If moving in same direction:
Time = Sum of Lengths / Difference of Speeds
Shortcut #10: Boats and Streams Shortcut
Downstream Speed
Boat + Stream
Upstream Speed
Boat − Stream
Shortcut #11: Finding Boat Speed
Boat Speed = (Downstream + Upstream)/2
Shortcut #12: Finding Stream Speed
Stream Speed = (Downstream − Upstream)/2
Shortcut #13: Circular Track Trick
Same Direction
Time = Circumference / Difference of Speeds
Opposite Direction
Time = Circumference / Sum of Speeds
Shortcut #14: Race Problem Technique
If A beats B by x meters:
Speed Ratio = Distances Covered in Same Time
Shortcut #15: Percentage Change in Speed
If speed increases by x%:
Reduction in Time = [x / (100 + x)] × 100%
If speed decreases by x%:
Increase in Time = [x / (100 − x)] × 100%
Shortcut #16: Relative Speed Memory Rule
| Movement Type | Relative Speed |
|---|---|
| Same Direction | Difference of Speeds |
| Opposite Direction | Sum of Speeds |
Shortcut #17: Unit Conversion Memory Table
| Conversion | Operation |
|---|---|
| km/h → m/s | × 5/18 |
| m/s → km/h | × 18/5 |
Shortcut #18: Time Saving Approximation
In MCQs:
- Use approximation when answer options are far apart.
- Cancel common factors before multiplication.
- Simplify ratios early.
Shortcut #19: Quick Average Speed Trick
For equal distances:
Average speed is always less than arithmetic mean.
This helps eliminate wrong options quickly.
Shortcut #20: Distance Ratio Technique
When time is same:
Distance Ratio = Speed Ratio
When speed is same:
Distance Ratio = Time Ratio
Important Formula Summary
| Concept | Formula |
|---|---|
| Speed | D/T |
| Distance | S × T |
| Time | D/S |
| Average Speed | Total Distance / Total Time |
| Equal Distance Average Speed | 2xy/(x+y) |
| Relative Speed | Sum or Difference |
| km/h to m/s | × 5/18 |
| m/s to km/h | × 18/5 |
| Boat Speed | (U + D)/2 |
| Stream Speed | (D − U)/2 |
Important Exam Tips
- Always convert units before calculations.
- Memorize all standard formulas.
- Use harmonic mean for equal distances.
- Practice train and boat problems regularly.
- Remember relative speed rules carefully.
- Simplify ratios before solving.
- Verify final answers properly.
Shortcut techniques in Speed, Time and Distance help candidates improve solving speed, reduce lengthy calculations, and solve aptitude questions efficiently in competitive examinations.