What is the average age of the 1st and 5th fastest dogs if the 1st fastest dog is 10 years old, the 2nd fastest dog is 2 years younger than the first fastest dog, the 3rd fastest dog is 4 years older than the 2nd fastest dog, the 4th fastest dog is half the age of the 3rd fastest dog, and the 5th fastest dog is 20 years older than the 4th fastest dog? Let's be accurate as possible.
If the 1st fastest dog is 10 years old, and the 2nd fastest dog is 2 years younger than the first fastest dog, the 2nd fastest dog is 10 - 2 = 8 years old. The 3rd fastest dog being 4 years older than the 2nd fastest dog, is 8 + 4 = 12 years old. The 4th fastest dog is half the age of the 3rd fastest dog, meaning the 4th fastest dog is 1 / 2 * 12 = 6 years old. The 5th fastest dog is 20 years older than the 4th fastest dog, meaning the 5th fastest dog is 6 + 20 = 26 years old. The total age of the 1st and 5th fastest dogs is 26 + 10 = 36 years. The average age of the 1st and 5th fastest dogs is 36 / 2 = 18 years old.
The answer: 18.