Answer:
The wood from boat is 17190 years old
Step-by-step explanation:
For first order radioactive decay-

where N is remaining amount of radioactive elements after "t" time,
is initial amount of radioactive element and
is half-life of radioactive element
Here
is 0.125,
is 5730 years
Plug-in all the values in the above equation-

or, t = 17190
so t is 17190 years or wood from boat is 17190 years old