150=1000e^-k30
thanks for reply but more help needed- can you show all the steps!

Question

150=1000e^-k30
thanks for reply but more help needed- can you show all the steps!

anonymous · Answer

$$150=\frac{ 1000 }{ e ^{30k} }$$
k=?
Right?

anonymous · Answer

$$\frac{150}{1000}=e^{-30k}$$
$$ \ln \frac{150}{1000} = -30k$$

anonymous · Answer

yep got there -can you keep going

anonymous · Answer

just divide by -30 ^_^

anonymous · Answer

you could also do this
$$\ln \Bigg[ \Big(\frac{15}{100}\Big)^{-\frac{1}{30}}\Bigg]=k$$

but it's equivalent to 

$$k=-\frac{1}{30}\ln\Big(\frac{15}{100}\Big)$$

anonymous · Answer

sorry im struggling
In 0.15 =k-30
-1.897=k-30
so k =0.06323
except book says thats the wrong answer                                                             ??

anonymous · Answer

what answer does the book give?

anonymous · Answer

k=0.005417

anonymous · Answer

hmm... i sec...

anonymous · Answer

I think the book is wrong... you can get that number with 150=1000e^(-350.2k) But other than that I dunno. Wolfram says that it's wrong, too (hit the approximate form on the real solution) http://www.wolframalpha.com/input/?i=150%3D1000e^%28-30x%29

anonymous · Answer

thanks !!! hope the teacher agrees