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put this solution on YOUR website!How long will it take a sample of radioactive substance to decay half of its
original amount, if it decays according to the function
A(t) = 450e^-0.249t , where t is the time in years?
Round to the nearest hundredth year.
:
Half of original amt: 450/2 = 225 [A(t)]
:
= 225
divide both sides by 450
=
= .5
then log equiv of exponents
-.249t*ln(e) = ln(.5)
ln of e is one so we have:
-.249t = -.693
t =
t = 2.78 yrs
:
:
Check solution on a calc; enter: 450*e^(-.249*2.78)= 225.2 half the original amt
