Question 630177
subtract the idle time in City B not moving:

41 - 20 = 21

d = vt

t = d/v

d/55 + d/45 = 21

LCM = 495

9d/495 + 11d/495 = 21

20d = 10395

d = 519.75 miles

CHeck:

519.75 / 55 + 519.75 / 45 = 9.45 hrs + 11.55 hrs = 21 hrs