Question 1158200
There used to be {{{a}}} carbon-14 but now there is only 0.18a carbon-14. So {{{e^(-0.00012t)=0.18}}}. Taking the natural logarithm of both sides gives {{{-0.00012t=ln(0.18)}}} Dividing both sides by -0.00012 gives {{{t=-ln(0.18)/0.00012}}} Since {{{ln(0.18)}}} is about -1.7148, we have {{{t=1.7148/0.00012=14290}}} years old.