The half-life of uranium-232 is 74 years In how many years will one third of the present quantity decay?

Use Q = Q0e-kt, where Q0 is the initial amount of uranium and k is the factor of proportionality. Since we know that Q = 1/2 Q0 when t = 74, we have 1/2Q0 = Q0e-k x 74; 1/2 = e -74k; In 1/2 = -74k; k = 0.009366853