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| Question 115033:  I need help solving this word problem:
 The debt on a certain credit card follows the function d=9000*1.015^t where d = debt in $ and t= time in months.
 A)How much debt will be owed in t=6 months?
 B)How long will it take for debt to exceed $15,000?
 I think i have A) here is what i did on it:
 d=9000*1.015^6
 d=$9,840.99
 And i couldnt finish b part but here is where i got:
 $15,000=9,000*1.015^t
 6,000=1.015^t
 I just dont understand how to get the t down from an exponent and finsih it for t!
 
 Any help is greatly appreciated THANKS!
 Answer by scott8148(6628)
      (Show Source): 
You can put this solution on YOUR website! $15,000=9,000*1.015^t ___ DIVIDING by 9000 gives 5/3=1.015^t 
 taking the logarithm gives log(5/3)=t*log(1.015) ___ (log(5/3))/(log(1.015))=t
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