Friday

April 18, 2014

April 18, 2014

Posted by **lala** on Tuesday, April 13, 2010 at 7:43pm.

a)Determine the half life of the substance

- Calculus -
**Reiny**, Tuesday, April 13, 2010 at 8:34pmFrom the equation we can see that the original amount was 100 units

So we want to know when that amount becomes 50

50 = 100(1.2)^-t

.5 = 1.2^-t

log(.5)= log(1.2^-t)

log(.5)= -tlog(1.2)

-t = log(.5)/log(1.2)

= -3.8

so t = 3.8 years is the half-life time

**Related Questions**

calculus - The rate at which an amount of a radioactive substance decays is ...

Science - Radioactive substance decays so that after t years, the amount ...

Physical Science - A gram of radioactive material has a half-life of one year. ...

College Algebra - The half-life of a radioactive material is about 34.6 years. ...

Algebra 2 help... - A half life of a certain radioactive is 36 days. An initial ...

Science - A material has 32 atoms in all; 24 decayed and the rest undecayed. If ...

AP Calculus - An Initial amount of 100 grams of Thorium-234 decays according to ...

physical science - A certain radioactive substance has a half-life of 1 hour. If...

Pre Calculus - Exponential Growth and Decay Find the half-life of a radioactive ...

Pre Calculus - Exponential growth and decay find the half life of a radioactive ...