Question 1008177
Many examples are made in this form of problem.  This data table shows the assigning of variables.

<pre>
                    RATE        TIME        DISTANCE
WITH WIND           r+w          t           {{{d[w]}}}
AGAINST WND         r-w          t           {{{d[a]}}}


KNOWN VARIABLES:   r, {{{d[w]}}}, {{{d[a]}}}
UNKNOWN VARIABLES:  t, w

</pre>
Question asks for w, the speed of the wind.  Note that time t is the same for both directions.


With wind,  {{{t=d[w]/(r+w)}}}
Against wind, {{{t=d[a]/(r-w)}}}
Equate the two formulas for time t.
{{{d[w]/(r+w)=d[a]/(r-w)}}}
{{{d[w](r-w)=d[a](r+w)}}}
{{{d[w]r-d[w]w=d[a]r+d[a]w}}}
{{{d[w]r=d[a]r+d[a]w+d[w]w}}}
{{{d[w]r-d[a]r=d[a]w+d[w]w}}}
{{{d[w]r-d[a]r=w(d[a]+d[w])}}}
{{{highlight(w=(d[w]r-d[a]r)/(d[a]+d[w]))}}}


Use the values given in your problem description to evaluate w.