Wednesday

April 1, 2015

April 1, 2015

Posted by **diane** on Wednesday, January 12, 2011 at 8:01am.

a certain element has a half life of 12 years. if there were 1000 milligrams originally, find the remaining amount after 20 years?

- math -
**drwls**, Wednesday, January 12, 2011 at 8:15am1000 mg*(1/2)^(20/12)

= 1000 mg*(1/2)^(5/3)

= 1000 mg*(1/2)^1.6667 = 315 mg

I used a hand calculator with a y^x key.

You can also use Google calculator.

http://www.google.com/search?q=1000*%281%2F2%29^%285%2F3%29&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

- math -
**Jessica**, Monday, January 24, 2011 at 8:53pmRatios and Rates.

Questions: What is the ratio of gold protons to silver protons with gold being 79 and silver being 47?

**Answer this Question**

**Related Questions**

PreCalculus - The half life of Carbon-14 is 5730 years. a. find the rule of the ...

Calculus - If 40 milligrams of strontium-90 radioactively decays to 12 ...

CALCULUS - A smoke detector contains 0.2 mg of Americium 241 (Am-241), a ...

Calculus - A smoke detector contains 0.2 mg of Americium 241 (Am-241), a ...

Calculus - A smoke detector contains 0.2 mg of Americium 241 (Am-241), a ...

Science - Can anyone help me find the half-life of strontium-90? I also need an ...

math - the half life of the carbon isotope C14 is about 5700 years. A. about how...

Chemistry - Which radioactive sample would contain the greatest remaining mass ...

Chemistry - the half-life of cobalt-60 is 5.20 years.. how many milligrams of a ...

Chemistry - Assuming an element's half-life is 3.6 years. How much of 2 grams of...