Question 1029290
Travel rates rule, RT=D

The faster plane goes the larger distance;
"while", indicated that the time quantities are equal for both planes

<pre>
                  rate            time            distance

oneplane          r+80            t                1750

otherplane        r               t                 950
</pre>

{{{system((r+80)t=1750,rt=950)}}}


{{{system(t=1750/(r+80),t=950/r)}}}


{{{1750/(r+80)=950/r}}}------solve this for r.




Note that another way is to start at the first shown system, perform the multiplication for the first equation (of the faster plane), and solve for t; and then use the second equation to solve for the value of r.