ALGEBRA
posted by PJ .
In 1920, the record for a certain race was 46.6 sec. In 1990, it was 45.9 sec. Let R(t)=therecord in the race and t=the number of years since 1920.
a)find a linear function that fits the data.
b) Use the function in (a) to predict the record in 2003 and in 2006.
c) Find the year when the record will be 45.7 sec.
Find a linear function that fits the data.
R(t)=

just like the one about salaries
m = change in seconds per year = (45.946.6)/(19901920) = .01 seconds / year
so
R = .01 *t + 46.6
check when t = 70 (that is 1990)
R = .01(70) +46.6 = 45.9 check
b) t = 2003  1920 = 83
R = .01(83) + 46.6 = 45.77
c) 45.7 = .01 t + 46.6
t = 90 years
90 + 1920 = 2010