algebra
posted by C .
In 1920 the record for a certain race was 45.4 sec. in 1950, it was 41.5 sec. let R(t) = the record in the race and t the number of years since 1920.
R(t)=?
What is the predicted record for 2003?
What is the predicted record for 2006?
in what year will the predicted record be 44.4 sec?

Your question is much too vague.
Are you suggesting the relation is linear? or exponential? or logarithmic?
You only have 2 ordered pairs, and then are trying to extrapolate.