Question 775695
Suppose B walks for T hours before overtaking A.
Thus in T hours, the distance travelled by B = 7T miles.


By this time the total distance travelled by A would be = the distance already covered when B started + the distance covered in T hours = 2.5x4.5 + 4.5T


Since at time T B overtakes A so the total distance travelled by them at that point of time should be equal.


{{{7T = 2.5*4.5+4.5T}}}
{{{2.5T = 2.5*4.5}}}
{{{T=4.5}}}


So the total distance covered by both A and B at the time T is 7 x 4.5 = 31.5 miles.