Correct Answer - Option 2 : 5 m/s
Given
A man travels first 50 km at 25 km/h, next 40 km at 20 km/h and then 90 km at 15 km/h.
Concept used
Average speed = (Total Distance) / Time taken
Calculation
T1 = 50/25 = 2 hr
T2 = 40/20 = 2 hr
T3 = 90/15 = 6 hr
Average speed
⇒ \(\frac{{50\ +\ 40\ +\ 90}}{{2\ +\ 2\ +\ 6}}\)
⇒ 18 km/hr
To convert it into m/s multiply with (5/18)
⇒ 18 × (5/18)
∴ 5 m/s