Brain challenge from 2/4/10 show.

Say Usain Bolt, Kelly and Perry were running a 100 meter dash race.
Suppose further that each ran at a uniform speed the whole race
If Usain beat Kelly by 10 meters and Kelly beat Perry by 10 meters, by how much did Usain beat Perry?


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    assume, usain did 100m in 10s. his speed must be 10m/s. In that time , kelly did 90m. her speed must have been 9m/s. Then kelly must have done 100m in 11.1s @ 9m/s
    perry did 90m in 11.1s
    his speed will be 8.1m/s. perry must have done 81m in 10s when usain did 100m.
    Then , usain must have been 19m ahead of perry!

    Perry is this correct,lol

    1. Avatar

      @Dami – You got it!!!

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