Hi there! I haven't done math in a while but I do well and I hope this helps. First, we get our radius from our area, which is about 4 inches. From there, I used the volume formula and got the answer closest to C, or 267.95. Thanks, good luck :)
I believe that she will need 56 square tiles. You get this by doing 7 times 8 which is 56. Then, since each tile is a one-foot square tile, you would need 56 tiles to cover the whole floor.
We need the half-life of C-14 which is 5,730 years.
Now, we will need a half-life equation:
elapsed time = half-life * log (bgng amt / ending amt) / log 2
We'll say beginning amount = 100 and ending amount = 41
elapsed time = 5,730 * log (100/41) / log 2
elapsed time = 5,730 * log (
<span>
<span>
<span>
2.4390243902
</span>
</span>
</span>
) / 0.30102999566
elapsed time = 5,730 * 0.38721614327 / 0.30102999566
elapsed time =
<span>
<span>
</span></span><span><span><span>5,730 * 1.2863041851
</span>
</span>
</span>
<span>elapsed time = 7,370.523 years
Source:
http://www.1728.org/halflife.htm </span>