Answer: there are 50 humans and 24 horses.
Explanation:
Let x represent the number of humans in the horse racing area.
Let y represent the number of horses in the horse racing area.
He counted 74 heads. A human has one head and a horse also has one head. It means that
x + y = 74
He counted 196 legs. A human has 2 legs and a horse has 4 legs. It means that
2x + 4y = 196 - - - - - - - -- - -1
Substituting x = 74 - y into equation 1, it becomes
2(74 - y) + 4y = 196
148 - 2y + 4y = 196
- 2y + 4y = 196 - 148
2y = 48
y = 48/2 = 24
x = 74 - y = 74 - 24
x = 50