Question 1102922
<pre>
The assignment of a variable for one of the times is implied here:

             SPEED      TIME      DISTANCE
Part 1        115         x        115x
Part 2        125        7-x     125(7-x)
Total                     7        855
</pre>

{{{highlight_green(115x+125(7-x)=855)}}}

Knowing how to form that equation and being able to solve it is all you need to understand.
SOLVE FOR x AND EVALUATE THE OTHER TIME QUANTITY.