The exponential function N = 500 × 0.74t, where t is measured in years, shows the amount, in grams, of a certain radioactive substance present. (a) Calculate N(4). (Round your answer to one decimal place.)  Explain what your answer means. After *blank  years there are *blank grams of the radioactive substance present. (b) What is the yearly percentage decay rate? (Round your answer to one decimal place.)

Suppose that $50,000 from a retirement account is invested in a large cap stock fund. After 25 yr, the value is $155,732.09. Part: 0 / 2 Part 1 of 2 (a) Use the model A = Pet 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 %. X S

The formula for interest compounded continuously is A=Pert  where P is the principal, i.e. the amount invested, r is the annual rate expressed as a decimal, and A is the amount at the end of t years.  Use this information to do the next problem. 20.  If you invest, $8950 at the annual rate of 6.75% compounded continuously, how much money will be in the account at the end of 15.75 years?