A car averages 45 mph for the first 4 hours of a trip and averages 75 mph for each additional hour. The average speed for the entire trip was 65 mph. How many hours long is the trip?	Choose one
A) 12  B) 11  C) 10  D) 9  E) 8
Let the time for which car averages 75 mph = t   65*(t+4)= 45*4 + 75 t   =&gt;10 t= 80   =&gt; t = 8   Total duration of the trip = 8+4= 
<gadget id="calculator">8+4</gadget>
<output>12</output>
12   12nswer 12
<result>A</result>
A car averages 45 mph for the first 4 hours of a trip and averages 75 mph for each additional hour. The average speed for the entire trip was 65 mph. How many hours long is the trip?