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September 23, 2014

September 23, 2014

Posted by **Anonymous** on Wednesday, November 10, 2010 at 5:54pm.

The mass of a radioactive element at time x is given by the equation below, where c is the original mass and h is the half-life of the element. The half-life of a substance is 5.6 years. How long will it take for 90 grams to decay to 22 grams? (Round your answer to one decimal place.)

M(x) = c (.5^{x/h})

- Physics HELP HELP -
**bobpursley**, Wednesday, November 10, 2010 at 8:17pm22=90 (1/2)^t/5.6

22/90=1/2^t/5.6

log (22/90)= t/5.6 log .5

t= 5.6 log (22/90)/log .5

log (22/90)=-.6118

log .5= -.3010

I am uncertain what you did.

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