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How long it takes for 80% of the carbon-14 to decay in an animal after it has died.

Carbon decays rate 0.012% per year.

So, my understanding is,

-(R = 0.00012 yr-1, t=1 yr)

R=Ro exp (-λt)

0.00012=Ro exp(-λ(1)) ---- (1)

-No = 0.8,

No=λRo

Ro=0.8/λ ------ (2)

To find λ, (2) into (1)

0.00012=0.8/λ exp(-λ(1))

∴ λ = 8.8 yrs-1

Now im stuck which equation i have to use to find the year?

Are my assumption above is correct?

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# Carbon-14 in a dead animal

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