Let h be the number of horses.
Since the number of men is equal to the number of horses, the number of men is also h.
Half of the owners (men) are riding their horses, and the other half are walking and leading their horses.
Legs from walking men:
Legs from walking men = h / 2 × 2 = h
Legs from horses:
Legs from horses = h × 4 = 4h
Total legs:
Total legs = Legs from walking men + Legs from horses = h + 4h = 5h
The total number of legs on the ground is given as 70:
5h = 70
h = 70 / 5 = 14
The number of horses is 14.