Question 107374
You know his speed on the return trip because it was given: 10 mph.  Now we need to find out how far he travelled.


{{{d=rt}}} is the formula for distance, given speed and time.  We should be able to assume that he drove just as far going to the meeting as he did coming back.


{{{d= 10mph * 4 hrs}}}
{{{d= 40 miles}}}


Now we need to rearrange our formula by dividing both sides by t, allowing us to say that:


{{{r=d/t}}}
{{{r=40m/3hrs}}}
{{{r=13.33...}}}

So he averaged 13 and 1/3 miles per hour on the trip to the meeting.



He must have been on the I405 in Los Angeles during rush hour.