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NOTE: Anybody interested in understanding how radioactive substances decay with time, should read this page which very clearly explains it:

http://math.usask.ca/emr/examples/expdeceg.html

The answer is 36.

No!. k is not (-1/29). k is calculated as ln(1/2) / 29=-0.02390162. k is ALWAYS a number < 0.

So, your equation becomes: 85/10 =85 * e^(=-0.02390162 x t). Now, if you solve for t, you should get:

t=96.34 years. Remember that 29 is half-life. So that: 1/2 ^(96.34/29)=~ 1/10 of the original amount.

At time equal to 0 years(t=0),the original isotope has 85

when dropped to 1/6,the isotope has 85/6

substitute it into M(t) and we have

\(85/6=85*e^\left (-t/719 \right )\)  

\(1/6=e^\left (-t/719 \right )\)

ln(1/6)=-t/719

-ln(6)=-t/719

ln6=t/719

t=719*ln6

t=ln(6^719)=1*ln(6^719)

6^719 about equal to infinity

Please show me how to do the work for the question 25 divided by 4

But we are given the equation of how this particular substance decays, with k = (-1/29)     = -.03448     whay are you calculating ANOTHER  (different)  k ???

147 / 52  =

2.826(923076).........    note, the 923076 part repeats

just didvide your two numbers

(e^x+5)/(9e^-x+4)=2  =  multiply both sides by (9e^-x+4)

e^x + 5   =  2 (9e^(-x) + 4)     simplify

e^x + 5  = 18e^(-x) + 8     

e^x - 3 - 18e^(-x)  = 0        multiply through by  e^x

e^2x - 3e^x - 18 = 0    factor

(e^x - 6) (e^x + 3)  = 0

Setting both facotrs to 0

e^x + 3  = 0      has no real solution

e^x - 6  =  0      add 6 to both sides

e^x =  6      take the natural log of both sides

ln e^x =  ln 6        and by a log property, we can write

x* lne = ln 6        and ln e  = 1 so we can ignore this

x =  ln 6

-1/3/ -1 2/3

Note that   - [1 + 2/3]   = - [ 5/3].....so we have

- [ 1/3] / - [5/3]   =

[ 1 / 3] / [ 5 / 3 ] =

1/3 *  3/5   = 

3/15  =

1/5

ok ..........................!!!!!

1.02857 x 10^(-1)   is one way....

engineers would say  102.857 x 10 ^(-3)

(1/8) / 6   =

(1 / 8) *   (1 / 6)   =

1 / 48

Math

Let N  = the original number of ducks

So we have.....

3N + 11 = 4N - 13     add 13 to both sides, subtract 3N from both sides

N = 24

Post your question.........!!!

The ratio of the ones that don't have to go to Summer School  =

[28 - 4] / 28   =

24 / 28   =

6 / 7

 4 8 12 ? 20 24

The difference between terms is 4....so.....

? = 16

First, there is approximately 365 1/4 days in a year NOT 355 ....  so every FOUR years we have a LEAP DAY (Feb 29th)... that is a LITTLE off too, so every few years a LEAP SECOND is added to keep things accurate.

the days ARE 24 hours (defined as the rotation time of the earth around its axis)....only the YEAR (defined as the time of the earth's ORBIT around the sun)  has a 1/4 day longer than 365...i.e.  the DAYS aren't longer, the YEAR is.

but your question asks what .oo281491907  is.....    that is the fraction of an hour in your (sorry,...incorrect) calculations

.0028149 (3600) = 10 . 133 seconds/day

CONGRATULATIONS    max