SOLUTION: The currrent, I0 (measured in amperes), decreases to I amperes after t seconds according to the formula I = I0e−0.51t. When 25 amperes decreases to 2.5 amperes, the equation

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Question 1026192: The currrent, I0 (measured in amperes), decreases to I amperes after t seconds according to the formula I = I0e−0.51t. When 25 amperes decreases to 2.5 amperes, the equation is 2.5 = 25e−0.51t. Rounded to the nearest tenth of a second, how long, t, does it take for the current to decrease from 25 amps to 2.5 amps?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
I+=+I%5B0%5De%5E%28-0.51t%29
When I%5B0%5D+=+25 and I = 2.5, we have 2.5+=+25e%5E%28-0.51t%29.
==> e%5E%280.51t%29+=+25%2F2.5+=+10
==> 0.51t = ln10 ==> t+=+ln10%2F0.51+=+4.5seconds.