Friday

November 28, 2014

November 28, 2014

Posted by **Dee** on Sunday, November 17, 2013 at 4:10pm.

____hr

- college algebra -
**Steve**, Sunday, November 17, 2013 at 4:14pmIf there was 40% more, then that's 1.4 times what's there now.

So, starting with an original amount of 1, there is now 1/1.4 of it left.

(1/2)^(t/8.4) = 1/1.4

Now just solve for t hours.

Note: It will be less than 8.4, since 8.4 hours ago, there was 100% more.

- college algebra -
**Dee**, Monday, November 18, 2013 at 9:24pmnot sure how to find the t, tried using the log approach but can't get the right answer.

**Answer this Question**

**Related Questions**

college algebra - Use a calculator to help solve the problem. An isotope of lead...

College Algebra - Use a calculator to help solve the problem. One isotope of ...

Half-life - After two hours, 1/16 of the initial amount of a radioactive isotope...

linear/exponential - This question involves the half-life formula. In this ...

Calculus Help Please!!! - A radioactive substance has a half-life of 4 days. ...

Chemistry Help Please!!! - A radioactive substance has a half-life of 4 days. ...

chm - An unknown radioactive substance has a half-life of 3.20 . If 34.8 of the ...

Math. Have answer, please show work - In a tracer method the potassium isotope ...

physics - The half-life of a certain radioactive isotope is 32 hours.What ...

algebra - The half-life of plutonium-234 is 9 hours. If 40 milligrams is present...