The Kentucky Derby has 20 horses. But yeah, it's different from race to race. It's rare that there is more than 20 horses, but it happens. Usually 10-20, but sometimes only 2. But the Grand National has 40 horses.
1320
yes
It must be a three year old.
Barbaro was three when he was humanely put down.
The Kentucky Derby is a horse race, you would win it on a horse, specifically a three year old Thoroughbred.
If the odds of a horse winning a horse race are 2 to 7 then the odds against that horse winning the race are 7 to 2.
Yes, it WAS a race, it is no longer a horse race.
If I understand your question correctly, if only three horses race, would you win no matter what? You would only win if you bet on the winning horse to "win." When you bet on a horse race, you also bet on what position that horse finishes. You may bet on a horse to "win, place, or show" or all three (each bet costs more money). If the horse comes in first, second, or third, and you bet all three, you would still get a payout. There are numerous combinations to wagering, Exactas, Trifectas, etc. and even in a three horse race, if you didn't bet correctly, or on the right horse, you could still lose.
Whirlaway was a slight horse, weighing only around 1025 pounds as a three year old.
It will take three times the feed of any other horse just to keep the ribs from showing.
The rider of a horse in a race is called a Jockey.
A horse race in which the owner declares before the race how much the horse will be offered for sale after the race.