The world record time for a certain swimming event was 63.2 seconds in 1950. Each year thereafter, the world record time decreased by 0.4 second.

(a) Use a formula to express the world record time as a function of the time since 1950. (Let t be the time in years since 1950 and R the record time in seconds.) R =

(b) Express using functional notation the world record time in the year 1975.

R

Calculate the world record time in the year 1975. sec