Question 1154830
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The ratio of the speeds is 100/165.


Hence, the entire time of 30 minutes consists of two time intervals with the reciprocal ratio.


So, the time for the 100 km trip is  {{{(30/(100+165))*165}}} =  18.68 minutes (approximately).    <U>ANSWER</U>
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Alan, 


notice that your answer 33/41 hours = {{{(33/41)*60}}} = 48.3 minutes is LONGER than 30 minutes (!)