There are two people, a and B. A walks 65 meters per minute and B 55 meters per minute. After B walks for six minutes, a chases B from behind. How many minutes can a chase B 40 meters away? First floor, I can't solve this equation

There are two people, a and B. A walks 65 meters per minute and B 55 meters per minute. After B walks for six minutes, a chases B from behind. How many minutes can a chase B 40 meters away? First floor, I can't solve this equation

55*6=330
330-40=290
290 / (65-55) = 29 minutes