Exponential decay, growth: radioactive element, petri dish

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
Posts: 7
Joined: Tue Mar 27, 2012 5:51 am

Exponential decay, growth: radioactive element, petri dish

Postby orange1998 » Thu Apr 05, 2012 2:54 am

A radioactive element has a count of 120. Four weeks later, the count is 104. Find the daily rate of decay.

Another one I need help with...

A petri dish contains a bacteria count of 6000. Two days ago, the count was 9720. What will the count be 5 days from now if the daily rate remains the same??

I do NOT get this at alllll! lol, I need the answers to these ASAP, like, tonight? Cause this is on my VERY high point homework assignment, last one of the quarter... :)

User avatar
Posts: 1733
Joined: Mon Dec 08, 2008 4:22 pm

Postby stapel_eliz » Thu Apr 05, 2012 12:32 pm

orange1998 wrote:I do NOT get this at alllll!

These should work very similarly to this other exercise that you have successfully completed. Try applying that method to these exercises.

For instance, for the first exercise in this thread, they have given you "9720 = 6000b2". Solve for "b", and interpret, just like for the exercise in the other thread. :wink:

Return to “Intermediate Algebra”