Question 1089978: The athlete was afraid because the coach's anger increased exponentially. Only 20 minutes after practice began, the coach was twice as angry as when the practice began. How many times more angry will the coach be at the end of the three hour practice?
--I know there is a formula to help solve this type of problem, but I do not remember it. I would appreciate any sort of help, thanks!
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! y=ab^x
let y=1 at x=0 minutes
1=ab^0, so a=1
2=ab^20=b^20
b=1.03526
without rounding, raise b to the 180 th power. That is 512.
He will be 512 times more angry or 256 times as angry as he was after 20 minutes (the question isn't clear on that).
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way 2
His anger doubles every 20 minutes
3 hours is 9 doublings.
2^9=512.
This is not linear. If it were linear, it would be y=ax and when x increased from 20 to 180, y would increase 9 fold. If it were twice as much at 20 minutes, it would be 18 times as much in 180 minutes, not 512 times.
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