Question 1166067
y for both distances, because "return trip".
Assuming "improved" meant to be "increased".

Return trip, speed was INCREASED TO,...

<pre>
                      SPEED       TIME         DISTANCE

first part             60                       y

second part            80                       y

totals
</pre>


Use {{{system(RT=D,D/T=R,D/R=T)}}}.


Find expression for the total traveling time:
<pre>
                      SPEED       TIME         DISTANCE

first part             60         y/60            y

second part            80         y/80            y

totals                       {{{highlight(y/60+y/80)}}}
</pre>