Question 257225
This is an RTD problem. Here is the table based on the given information:
speeds  . . . . . . . . . rate . . . . . . . . . . . .time . . . . . . . . . . . .distance
A . . . . . . . . . . . . . . 40 . . . . . . . . . . . . x . . . . . . . .. . . . . . .. . 40x
B . . . . . . . . . . . . . . 45 . . . . . . . . . . . . 4-x . . . . . . . . . . . . . . 180 - 45x
average . . . . . . . . . . . . .. . . . . . . . . . .. 4 . . . . . . . .. . . . . .. . . . .
The distances must be equal, so
{{{40x = 180 -45x}}}
{{{85x = 180}}}
{{{x = 2.11764706}}}
The distance is: ~ 84.71 miles