1. The half-life of a radioactive element is 131 days, but your sample will not be useful to you after 90% of the radioactive nuclei originally present have disintegrated. Using the half-life function M(x)=c(0.5)x/h, about how many days you can use the sample?
[A]435 440 [C]445 [D]450
I don't know where to start on this, just messes me up.
2. Cheryl invests $270 at 7% compounded continuously.
A. Write an exponential function to model the situation. (I got 270e^0.07t)
B. At what time (As in years) will the total reach $800? (I got 1.416076726)
3. Using the formula R=log10 I, where R is the measurement of the Richter scale, and I is the intensity, to find the Richter scale measurement of an earthquake with intensity 102,000,000 ergs.
[A]435 440 [C]445 [D]450
I don't know where to start on this, just messes me up.
2. Cheryl invests $270 at 7% compounded continuously.
A. Write an exponential function to model the situation. (I got 270e^0.07t)
B. At what time (As in years) will the total reach $800? (I got 1.416076726)
3. Using the formula R=log10 I, where R is the measurement of the Richter scale, and I is the intensity, to find the Richter scale measurement of an earthquake with intensity 102,000,000 ergs.