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April 17, 2014

April 17, 2014

Posted by **kelly** on Sunday, July 24, 2011 at 4:06pm.

R(t) = 46.5 - t*0.02

what is the predicted record in 2003? 44.84

what is the predicted record in 2006?44.78

what year will the record be 44.58 seconds? 2015

help me figure this out, first I subtract 46.5 - 45.3 = 1.2 next 1980- 1920 = 60 1.2/60 = 0.02

are these correct

- algebra -
**Damon**, Sunday, July 24, 2011 at 5:04pmt = year - 1920

r = m t + 46.5

in 1980 t = 1980 - 1920 = 60

r = m (60) + 46.5 = 45.3

so

m = (45.3-46.5)/60 = -0.02

so

r = -0.02 t + 46.5 Our equation agreed

in 2003:

t = 2003 - 1920 = 83 years

r = -0.02 (83) + 46.5 = 44.84 agree

now for example in what year will it be 44 seconds?

44 = -0.02 t + 46.5

0.02 t = 46.5 - 44 = 2.5

so

t = 125

125 = year - 1920

so year = 2045 (that is just an example so you can do the real problem.)

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