How Long Will It Take a Sample of Radioactive Substance $\mathrm { A } ( \mathrm { t } ) = 250 \mathrm { e } ^ { - .223 \mathrm { t } }$

question 429

Multiple Choice

How long will it take a sample of radioactive substance to decay to half of its original amount, if it decays according to the functi $\mathrm { A } ( \mathrm { t } ) = 250 \mathrm { e } ^ { - .223 \mathrm { t } }$ , where t is the time in years? Round your answer to the nearest
Hundredth year.

• A) 27.87 yr
• B) 55.75 yr
• C) 3.11 yr
• D) 24.76 yr

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