Question 1001955
RT=D; use time quantities instead of points on a time line; set up a data table for rates, times, distances.  "Catch-up" is when Tobias and Tris went the same distance.  Best unit for time will be in the equivalents as HOURS.


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"~yes".


Time QUANTITIES are used here in unit of HOURS or fractions of hours.  
<pre>
              rate         time in hours     distance
Tobias         4           t+12/60            d
Tris           r            42/60-12/60       d
</pre>
The description is enough information to obtain two equations, but the system will have THREE unknown variables of r, t, and d.


--After some thought,  t=42/60-12/60 and time becomes a knowable constant for Tobias and another for Tris; making t as known.  Make this adjustment and the only unknowns are r and d.