SOLUTION: The equation R=-0.028t+20.8 can be used to predict the world record in the 200-m dash, where R is the record in seconds and t is the number of years since 1920. In what year will t

Question 620400: The equation R=-0.028t+20.8 can be used to predict the world record in the 200-m dash, where R is the record in seconds and t is the number of years since 1920. In what year will the record be 18.0 seconds?
I dont even know where to begin to find what year the record will be 18.0 seconds. This word problem really confused me bad... your time and efforts will be greatly appreciated in this word problem...Thank you very much for your help.
Answer by MathTherapy(10552) (Show Source): You can put this solution on YOUR website!

The equation R=-0.028t+20.8 can be used to predict the world record in the 200-m dash, where R is the record in seconds and t is the number of years since 1920. In what year will the record be 18.0 seconds?

R(t) = - 0.028t + 20.8
18 = - 0.028t + 20.8
0.028t = 20.8 � 18
0.028t = 2.8
t, or time for the record to be 18 secs = , or 100 years

100 years from the year 1920 = the

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