Question 1094907
<br>His afternoon speed is exactly twice his morning speed, so the afternoon trip takes exactly half as long as the morning trip.<br>
Since the total driving time was an hour and a half, the morning trip took an hour and the afternoon trip took half an hour.<br>
Using the time and average speed for either the morning or afternoon trip shows the driving distance to be 21 miles:
{{{21*1 = 21}}} or {{{42*0.5 = 21}}}