SOLUTION: Can someone please help me work through this? The number of insects attracted to a bright light is currently 5. If the number is expected to quadruple every 9 minutes, how long

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Question 331596: Can someone please help me work through this?
The number of insects attracted to a bright light is currently 5. If the number is expected to quadruple every 9 minutes, how long will it take for the number to reach 700?
____ minutes
Answer by galactus(183) About Me  (Show Source):
You can put this solution on YOUR website!
Initially, there are 5 bugs. If it quadruples in the first 9 minutes, there are 20 bugs.
20=5%2Ae%5E%28k%2A9%29
k=%282%2Aln%282%29%29%2F9
So, we have:


5%2Ae%5E%28%282%2Aln%282%29%2At%29%2F9%29=5%2A2%5E%282t%2F9%29
700=5%2A2%5E%282t%2F9%29
140=2%5E%282t%2F9%29
t=32.08 minutes