Two dice are rolled. use the complement rule to find that the sum of the dice is less than 10

17/20

there are 20 different sums but 3 of them add up to 10 and more such as 6+4=10, 5+5=10, 6+5=11

I believe it is 37 humans and 37 horses

Step-by-step explanation:

Divide the heads by 2, it will equal 37 heads so 37 horse heads and 37 human heads. If they are at a horse race they need 1 human to ride 1 horse so therefore that is why i divides it by 2. (hope thats right)