How do solve for the answer in the My question: area? What are the asking for to solve?

A sample of radioactive 214/83 Bi, which has a half-life of 19.9 min, has an activity of 0.0580 Ci. What is its activity 1.00 h later? Answer in Ci t= 1h R = 0.058 Ci R(t) = Roe the T = 19.9/ In 2 R = 0.058 e[-60/19.9/In2] = 0.058 e[-2.089] = 0.00718 Ci = 7.2 x 10-3 Ci My question: N(t) = ? N(t) = R(t)/ 1 = R(t) T= 0.0072(3.7 x 1010)(19.9/In 2) = 7.6 x 109 1 = 1/ T in Becquerel