Given that the decay rate of the uranium is given to be 57%, this means that on the second day only 43% of the Uranium-233 will be left. The equation therefore, that will allow us to answer the question is that,
A(t) = A(0)(1 - r)^n
where A(t) is the amount after n days, A(0) is the original amount, r is the decimal equivalent of the rate and n is the number of days. Substituting the known values,
A(t) = (3,820 pounds)*(1-0.57)^15
A(t) = 0.0121 pounds
This is unfortunately not found in the choices.
