Question 92001
The percent of a certain radiation that can penetrate x millimeters of lead shielding is given by r(x) = 100e^-1.5x. What percent of radiation, to the nearest tenth of a percent, will penetrate a lead shield that is 3 millimeters thick? 
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Let x = 3 and solve for r:
r(3) = 100e^(-1.5*3)
r(3) = 100e^(-4.5)
r(3) = 100*0.011089965
r(3) = 11.09 %
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Cheers,
Stan H.