Question 1183207
You mean, she traveled 30 miles per hour faster than on local roads?

<pre>
                 SPEED miles per hour   TIME hours        DISTANCE miles

Highway           20+30                 60/50=6/5              60

Local              20                   16/20=4/5              16

TOTALS                                    10/5=2               76
</pre>
Average speed for total trip, {{{(76/2)(miles/hour)=highlight(38(miles/hour))}}}