Friday

April 18, 2014

April 18, 2014

Posted by **Suzie** on Friday, February 24, 2012 at 5:47pm.

- math -
**Reiny**, Friday, February 24, 2012 at 7:24pmI will do the last part

to have only 2% of the intensity left,

l(t) = .02

.02 = 4^(-.0101t) (1)

ln .02 = -.0101t ln4

-.0101t = ln .02 /ln4 = -2.821928

t = -2.821928/-.0101 = 279.4

for the 50% question , set the left side equal to .5

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