Question 488292
<pre>
                speed, work rate         time         amount of work

John                1/30                      30                1

Wife                1/x                        x                1                                   

both together       1/18                       18               1       
</pre>

{{{1/30+1/x=1/18}}}-----solve this basic equation.


{{{1/x=1/18-1/30}}}


{{{540=30x-18x}}}


{{{12x=540}}}


{{{highlight(x=45)}}}