Question 357299
let c be the distance from A to B (and vice-versa).  Then his time of travel from A to B is c/6 hrs.  Similarly, his time from B to A is c/8.  His total time of travel is then {{{c/6+c/8 = 7c/24}}}hrs.  His total distance traveled is 2c.  Therefore his average speed is {{{(2c)/(7c/24) = 48/7}}} miles per hour.