Question 345948
both ways the distance traveled  is the same.

time * speed forward = time * speed on return
let speed while going be x mph. time = 7 hours
return speed = x+12. time = 5 hours
7x=(x+12)*5
7x=5x+60
7x-5x=60
2x=60
x=30 mph speed  forward
time = 7 hours
..
distance = 7*30 = 210 miles