Question
Download Solution PDFMr. W travelled 370 km, 390 km and 720 km at speeds of 37 km/hr, 5 km/hr and 8 km/hr, respectively. Find his average speed in km/hr.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven:
Distance 1 (d1) = 370 km
Speed 1 (s1) = 37 km/hr
Distance 2 (d2) = 390 km
Speed 2 (s2) = 5 km/hr
Distance 3 (d3) = 720 km
Speed 3 (s3) = 8 km/hr
Formula used:
Average speed = Total Distance / Total Time
Total Distance = d1 + d2 + d3
Total Time = (d1 / s1) + (d2 / s2) + (d3 / s3)
Calculations:
Total Distance = 370 + 390 + 720
⇒ Total Distance = 1480 km
Total Time = (370 / 37) + (390 / 5) + (720 / 8)
⇒ Total Time = 10 + 78 + 90
⇒ Total Time = 178 hours
Average Speed = Total Distance / Total Time
⇒ Average Speed = 1480 / 178 = 740 / 89
⇒ Average Speed = 8
∴ The correct answer is option (2).
Last updated on Jul 21, 2025
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