Answer:
it's 24 ...................
Let 
be the scores of the first 8 quizzes. We know that the average of these scores is 85, so we have
The average of the first 9 scores is 81, and it is given by
But we know that the sum of the first 8 is 680:
And we can solve for the nineth score: multiply both sides by 9:
Subtract 680 from both sides:
Since the value 0.98 is less than 1, we can therefore say that balance in this account is decreasing.
<h3>
How to recognize Exponential Function.</h3>
Exponential Function can be used for increase rate and also for decay rate. The difference between the two are the plus and minus signs. To put it in another perspective, If Y = P(M)³
If M is less than one, that means it is decaying or decreasing. And if M is greater than one, that means it is increasing.
Given that Some banks charge a fee on savings accounts that are left inactive for an extended period of time. And the equation
y = 5000(0.98)^x represents the value, y, of one account that was left inactive for a period of x years.
According to the equation, to know if the balance in this account is increasing or decreasing, we will analyze the value 0.98.
Since the value 0.98 is less than 1, we can therefore say that balance in this account is decreasing.
Learn more about Exponential Function here: brainly.com/question/2456547
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80 x 3/10 = 240/10 = 24 times
