<PRE><B>Question 960356</B>
Uniform Rates for Travel according to RT=D rate time distance.
{{{1/3}}} of an hour is 20 minutes.


________________speed__________time____________distance
Speed x__________x_____________t-1/3___________280
Speed x-8_______x-8____________t_______________280


The two hypothetical trips are the same distance, but you find not much use  in equating the expressions for the distance.  You use RT=D, and make a system of two equations in x and t.


{{{system(x(t-1/3)=280,(x-8)*t=280)}}}


Solve the system for x.  The arithmetic (or algebraic steps) should be a non-stressful chore.</PRE>