Question 1149743
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<pre>

From 11:30 am to 1:54 pm, the time is {{{30/60}}} + {{{1}}}{{{54/60}}} = 0.5 + 1.9 = 2.4 hours.


At the average rate of 50 km/h, the distance is  2.4*50 = 120 kilometers.


From 11:30 am to 12:45pm, the time is  {{{30/60}}} + {{{45/60}}} = {{{75/60}}} = 1.25 hours.


Hence, the required average rate under the question is  {{{120/1.25}}} = 96 km/h.  <U>ANSWER</U>
</pre>

Solved.


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Notice that this fragment in the problem's condition &nbsp;"but if he averages 80 km/h he arrives at 1 p.m." &nbsp;is &nbsp;EXCESSIVE &nbsp;info. 


It is &nbsp;NOT &nbsp;NECESSARY &nbsp;and is not used in the solution.