SOLUTION: Problems A-C are complete, I need help with d and e. Please. Students in an english class took a final exam. They took equivalent forms of the exam at monthly intervals thereafter

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Question 212859: Problems A-C are complete, I need help with d and e. Please.
Students in an english class took a final exam. They took equivalent forms of the exam at monthly intervals thereafter. The average score S(t), in percent, after t months was found to be given by S(t)=68-20log(t+1), t> or = to 0.
a)What was the average score when they initially took the test, t=0?
68%
b)What was the average score after 4 months? 54% And after 24months? 40%
c)After what time t was the average score 50%? 6.9 months
d) What upper limit might be placed on t?
e) In practice, would this upper limit ever be enforced? Why?

Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!
Problems A-C are complete, I need help with d and e. Please.
Students in an english class took a final exam. They took equivalent forms of the exam at monthly intervals thereafter. The average score S(t), in percent, after t months was found to be given by S(t)=68-20log(t+1), t> or = to 0.
a) What was the average score when they initially took the test, t=0? 68%
b) What was the average score after 4 months? 54% And after 24months? 40%
c) After what time t was the average score 50%? 6.9 months
d) What upper limit might be placed on t?

(This tests how much knowledge people forget after they finish 
taking a class.)

68% because the "-20log(t+1)" is always subtracted from 68
and the percentage would be 68% only at the beginning and
decrease from there. 

e) In practice, would this upper limit ever be enforced? Why?

Enforced?  That doesn't make any sense!  You can't "enforce" 
somebody to make a certain grade on a exam in a course they 
completed t months ago. What do they do?  Lose credit for
taking the course if they don't remember enough of it to pass
an exam on it  after so many months and make them take the
course over?  I don't get it. Sorry. 

Edwin

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