Answer:
the cloth is old by 1,844 years
Explanation:
The computation is shown below:
The half-life of C^(14) is 5730 years
Now
[tex]\lambda[/tex] =1.210 × 10^-4 years^(-1)
Now
[tex]N(t) = Ce^{-\lambda\times t}[/tex]
[tex]0.8 \times (N_0) = N_0 \times e^{-\lambda \times t}\\\\ln(0.8) = (-\lambda \times t)\\\\t = \frac{-(ln(0.8))}{\lambda}[/tex]
[tex]\lambda[/tex] = .000121,
so t = 1844 yrs
hence, the cloth is old by 1,844 years