Question 1208018
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The time t that it takes to get to school varies inversely with your average speed s.

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That says what it says and means just what it says.
You need a constant factor for variation.  k.


{{{t=k(1/s)}}}

{{{t=k/s}}}



part (a)
{{{t=40}}} minutes and {{{s=30}}} miles per hour.
So what is k value?

{{{ts=k}}}

{{{k=40*30}}}

{{{k=1200}}}


The equation you want to use is then become {{{t=1200/s}}}.


part (b)
Just use the same equation but now know that {{{s=40}}}.