Correct Answer - Option 3 : 26.6 kmph
Given:
Average of speed during uphill (S1) = 24 kmph
Average of speed during down (S2) = 30 kmph
Formula used:
Average speed = (2 × S1 × S2)/(S1 + S2)
Calculation:
Average speed = (2 × 24 × 30)/(24 + 30)
⇒ 1440/54
⇒ 26.66 kmph
Hence, The average speed of the entire journey is 26.66 kmph.