Gani — AI Math Tutor | Karka LMS

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Speed & Distance

· Examples

✏️ Worked Examples — Step by Step

Easy

A car travels 240 km in 4 hours. What is its average speed?

💡 Speed = Distance ÷ Time.

👁 Show Solution

Speed = 240 ÷ 4 = 60 km/h

✅ Answer: 60 km/h

✅60 km/h

Medium

A train running at 72 km/h crosses a 200 m long platform in 15 seconds. What is the length of the train?

💡 Convert km/h to m/s (× 5/18). Train + platform = total distance.

👁 Show Solution

72 km/h = 72 × 5/18 = 20 m/s
Total distance covered in 15 s = 20 × 15 = 300 m
Train length = 300 − 200 = 100 m

✅ Answer: 100 m

✅100 m

Challenging

A man covers a distance of 60 km at 30 km/h and returns at 60 km/h. Find his average speed for the whole journey.

💡 For equal distances, average speed = 2uv/(u+v) — harmonic mean, not arithmetic.

👁 Show Solution

Avg speed = 2uv / (u+v) = 2×30×60 / (30+60)
= 3600 / 90 = 40 km/h

✅ Answer: 40 km/h

✅40 km/h

Examples