Question

Carbon dating. How old is an ivory tusk that has lost 40% of its carbon-14?

Answer 1

You need the half-life of C-14 which is 5730 years.

Answer 2

The formula is elapsed time = 5,730* log [(begng amt)/(ending amt)]/ log 2
time = 5,730 * log (100%/40%) log 2
time = 5,730 * log 2.5 / log 2
time = 5,730 * 0.3979400087 / 0.3010299957
time = 7,575 years
and a calculator to check your answer
http://www.1728.org/halflife.htm

Answer 3

Oh I see. Thanks that helped out alot

Answer 4

Hmmmmmmmm LOST 40% so that means 60% remains.
have to recalculate
5,730 * log(100%/60%) / log2

Answer 5

5,730 * log(1.6666666666) / log 2
5,730 * 0.2218487496 / 0.3010299957
=4,222.8 years or rounded
4,223 years