Question 728536
You could make a data table this way:

Let r = the rate of the slower team (arbitrary if you make r for slower team or faster team);


Team____________rate____________time______________distance worked
Slow____________r_______________3_________________r*3
Fast____________r+2_____________3_________________(r+2)*3
Total__________________________ __________________18


You might be able to think of their rates as additive, even without making a table like shown above.  The sum of their distances worked in the three hour time period is the original gap between them of 18 miles.  {{{3r+3(r+2)=18}}}.  Solve for r and then compute {{{r+2}}}.