Question 1087930
<pre>
Speed going to her parents , r+24
Speed coming back home, r


                     RATE          TIME          DISTANCE
GOING TO             r+24          560/(r+24)      560
RETURN HOME          r             560/r           560
Total                               16
</pre>

{{{560/(r+24)+560/r=16}}}

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{{{35/(r+24)+35/r=1}}}

{{{35r+35(r+24)=r^2+24r}}}

{{{35r+35r+35*24=r^2+24r}}}

{{{r^2+24r-70r-35*24=0}}}

{{{r^2-46r-35*24=0}}}

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discriminant is {{{74^2}}}


{{{r=(46+- 74)/2}}}
choose the positive value of r.

{{{r=(46+74)/2}}}

{{{highlight(r=60)}}}, trip home, speed
{{{highlight(84)}}}, trip going to parents