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

Algebra ->  Customizable Word Problem Solvers  -> Misc -> 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      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 620405: 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?
This is a confussing word problem....I was looking for kingme 18 but couldnt find any way to contact him he did a great job on the last word problem I sent in for help with...If your out there please help me again, your awesome...
Answer by nerdybill(7384) About Me  (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?
.
Set R to 18 and solve for t:
R=-0.028t+20.8
18=-0.028t+20.8
subtracting 20.8 from both sides:
-2.8=-0.028t
dividing both sides by -0.028:
-2.8/(-0.028) = t
100 = t
.
Since t is defined as "the number of years since 1920" we have:
1920+100 = 2020 (this is your answer)