I have a question about Calculating Avreage Speed

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Homework Help Overview

The discussion revolves around calculating average speed for a marathon run backwards, with a specific focus on converting time and distance into appropriate units. The original poster presents a problem involving a marathon time of 3 hours, 53 minutes, and 17 seconds over a distance of 42.2 kilometers.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the conversion of time from hours, minutes, and seconds into a single unit, as well as the formula for speed. There are inquiries about the original poster's method and requests for clarification on the time conversion process.

Discussion Status

Some participants have provided guidance on the formula for speed and the conversion of time, while others are seeking further clarification on the original poster's calculations. Multiple interpretations of the problem are being explored, but there is no explicit consensus on the correct approach yet.

Contextual Notes

The original poster's calculation appears to have led to an incorrect answer, prompting questions about the assumptions made in their method. There is an emphasis on ensuring that the units used for speed are correctly applied.

_wantana
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The question states that Running a marathon backwards the record is 3 h 53 min 17 s and the race is 42.2 km's and I am supposed to calculate avreage speed of the race in meters per second and kilometres per hour I found a way to convert the record into just hours and I divided by 42.2 and the answer was completely wrong because according to the book its 10.9km/h and 3.01m/s does anyone have any idea how to achieve this answer?
 
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[tex]s=\frac{d}{t}[/tex]
Speed is km/h, not h/km.
 
_wantana said:
The question states that Running a marathon backwards the record is 3 h 53 min 17 s and the race is 42.2 km's and I am supposed to calculate avreage speed of the race in meters per second and kilometres per hour I found a way to convert the record into just hours and I divided by 42.2 and the answer was completely wrong because according to the book its 10.9km/h and 3.01m/s does anyone have any idea how to achieve this answer?
Show your conversion of time to hour.
 
3 h 53min 17 s >3.29805556 hours
 
_wantana said:
3 h 53min 17 s >3.29805556 hours
Now v = d/t.
 

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