Answer:
The age of bones was estimated to be 11,462 years old.
Explanation:
Formula used :

where,
= initial mass of isotope
N = mass of the parent isotope left after the time, (t)
= half life of the isotope
= decay constant
We have:
= x, N = 25% of x = 0.25 x
t = ? .

Now put all the given values in this formula, we get

t = 11,462.4338 years ≈ 11,462 years
The age of bones was estimated to be 11,462 years old.