A cyclist covers two laps of a 600m circuit in 90 seconds. What is his average speed in km per hour?

  • 0 votes

This is a question from SGC Common Entrance Examination without answers. You may need to use your knowledge of the  speed, distance and time formulas!

Posted Fri 8th June, 2012 @ 11:09 by girlyrainbow

4 Answers

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I would first convert the time into hours so

90 secs=90/60minutes=1.5 minutes=1.5/60 hours=0.025hours

Then convert the distance into km so

2*600 (as two laps)= 1200m=1200/1000km=1.2km

Then use speed=distance/time

speed=1.2/0.025=48km/h

Hope this Helps! :)

Answered Fri 8th June, 2012 @ 11:37 by Dilly
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Thanks guys, I didn't simplify the question before using the speed, distance and time formula. Now I realise my mistake!!!

Answered Sat 9th June, 2012 @ 14:52 by girlyrainbow
  • -1 votes

Speed= distance/time so speed=1200m/90seconds.

1200/90=13.33m/s

notice the units are m/s. You need km/h.

1m/s=3.6km/h

3.6 x 13.33 = 47.98km/h

That should be right. Sorry if it's not but I don't see how it could be wrong!


Answered Fri 8th June, 2012 @ 11:38 by Hoosierette
Edited by Hoosierette on Fri 8th June, 2012 @ 11:40
  • -2 votes

Rember the triangle?

s  d^ t

soooo..

yue hav the distance and time soo as far as I know do >  d/t> 600m/90= 6.66 m/s < NOT SURE ABWT THE UNIT THOU

Hope this helped : D

Answered Fri 8th June, 2012 @ 11:13 by в