A car averages 65 mph for the first 5 hours of a trip and averages 75 mph for each additional hour. The average speed for the entire trip was 60 mph. How many hours long is the trip?
Choose the most appropriate option.
A) 9  B) 8  C) 7  D) 6  E) 5
Let the time for which car averages 75 mph = t   60*(t+5)= 65*4 + 70 t   =&gt;10t= 40   =&gt; t = 4   Total duration of the trip = 5+4= 
<gadget id="calculator">5+4</gadget>
<output>9</output>
9   9nswer 9
<result>A</result>
A car averages 65 mph for the first 5 hours of a trip and averages 75 mph for each additional hour. The average speed for the entire trip was 60 mph. How many hours long is the trip?