Question 765423
Distance = Speed * Time
Speed = x

    7x = 6x + 60
  7x - 6x = 60
       x = 60
Speed = 60mph
Proof:
7 * x = 6 * (x + 10)
7 * 60 = 6 * (60 + 10)
7 * 60 = 6 * 70
    420 = 420
Distance = 420 miles.
Hope this helps.
:-)