An animal carcass had 24 grams of carbon 14 when it was alive and 3 grams when its fossilized remains were discovered how old is the fossil?

The carbon 14 left from this animal is 3 grams of 24 grams which is: 3g/24g = 1/8 times of its original mass. Then, the age of the animal fossil would be:

final weight = initial weight * (1/2) ^ time/half-live

1/8 initial weight = initial weight * (1/2) ^ time/half-live

log2 1/8 = log2 (1/2) ^ time/half-live

-3 = - time/half-live

time = - 3 * - (half-live)

time = 3 half-live

If the half-live is 5730 years, the age would be: 3 * 5730 = 17.190 years.