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A man during a bike ride covers 30 mins at speed of 40 kmph, another 45 mins at 60 kmph and next 45 mins at 100 kmph speed. Find the average speed of man during the entire journey.1). 33.33 kmph2). 50 kmph3). 70 kmph4). 75 kmph |
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Answer» As per given data- A man travels 30 mins at speed of 40 KMPH. So, he travels 0.5 hr at speed of 40 kmph. ∴ Distance covered by man = speed of bike × time TRAVELED ⇒ Distance covered by man = 40 × 0.5 ⇒ Distance covered by man = 20 km---- (1) Next he travels 45 mins at 60 kmph So, he travels 0.75 hr at speed of 60 kmph. ∴ Distance covered by man = speed of bike × time traveled ⇒ Distance covered by man = 60 × 0.75 ⇒ Distance covered by man = 45 km---- (2) & then he travels 45 mins at 100 kmph So, he travels 0.75 hr at speed of 100 kmph. ∴ Distance covered by man = speed of bike × time traveled ⇒ Distance covered by man = 100 × 0.75 ⇒ Distance covered by man = 75 km---- (3) From above we can see total distance traveled by man is 20 + 45 + 75 = 140 kms. & total time taken to travel = 0.5 + 0.75 + 0.75 = 2 hrs. $(\THEREFORE Average\;speed\;of\;man = \frac{{Total\;distance\;traveles}}{{Time\;taken}})$ Average speed of man = 140/2 ∴ Average speed of man = 70 kmph. ∴ Man rode bike at average speed of 70 kmph. |
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