You are on an archeological dig with a research team from the local university. the team unearths some pieces of an ancient wooden boat. when a sample of the wood is analyzed for carbon-14, scientists determine that 12.5% (or1/8) of the original amount of c-14 remains. if the half-life of c-14 is 5,730 years, how old is the wood from the boat?

The wood from boat is 17190 years old

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

the answer for sodium is 0.186

the answer for rubidium is 0.251