On first two question I only need help with B

Suppose that $50,000 from a retirement account is invested in a large cap stock fund. After 15 yr, the value is $179,527.66. Part 1 of 2 (a) Use the model A= Pe to determine the average rate of return under continuous compounding. Round to the nearest tenth of a percent. Avoid rounding in intermediate steps. The average rate is approximately 8.5 %. Part: 1 / 2 Part 2 of 2 (b) How long will it take the investment to reach one-quarter million dollars? Round to the nearest tenth of a year. Round values in intermediate steps to three decimal places. X X 5 It will take approximately 10.8 years.The isotope of plutonium Pu is used to make thermoelectric power sources for spacecraft. Suppose that a space probe was launched in 2012 with 2.0 kg of 238 "Pu. Part 1 of 2 (a) If the half-life of Pu is 87.7 yr, write a function of the form O (t) = Coe "to model the quantity O (t) of Pu left after t years. Round the value of k to five decimal places. Do not round intermediate calculations. e (1) = 2e -0.0079t Part: 1 / 2 Part 2 of 2 (b) If 1.7 kg of Pu is required to power the spacecraft's data transmitter, for how long after launch would scientists be able to receive data? Round to the nearest year. Do not round intermediate calculations. Scientists will be able to receive data for approximately yr. X .Technetium-99 ( "To) is a radionuclide used widely in nuclear medicine. "To is combined with another substance that is readily absorbed by a targeted body organ. Then, special cameras sensitive to the gamma rays emitted by the technetium are used to record pictures of the organ. Suppose that a technician prepares a sample of To-pyrophosphate to image the heart of a patient suspected of having had a mild heart attack. Part: 0 / 2 Part 1 of 2 (a) At noon, the patient is given 10 mCi (millicuries) of "To. If the half-life of "To is 6 hr, write a function of the form O (t) = Coe *to model the radioactivity level Q (1) after t hours. Round k to four decimal places. Do not round intermediate calculations. The radioactivity level function is @ (t) = e X