A man goes to Jaipur from Surat at a speed of 3km/hr and returns to Surat at speed of 15km/hr, through same route. What is his average speed (in km/hr) of the entire journey?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 5.
Average speed for same distance ⇒ 2 × (Speed1 × Speed2) ÷ (Speed1 + Speed2)
⇒ 2 × (3 × 15) ÷ (3 + 15)
⇒ 2 × 45 ÷ 18
⇒ 90 ÷ 18
⇒ 5 km/hr