Solve the problem.
-If the formula $R=-0.037 t+50.1$ can be used to predict the world record in the 400 -meter dash $\mathrm{t}$ years after 1925, for what years will the world records be 48.1 seconds or less?
A) 1955 or after
B) 1979 or after
C) 1980 or after
D) 1981 or after

Question

Quizplus · Accepted Answer

To find when the record will be 48.1 seconds or less, set $R = 48.1$ and solve for $t$:  $48.1 = -0.037t + 50.1$  $0.037t = 50.1 - 48.1$  $0.037t = 2$  $t = \frac{2}{0.037} \approx 54.05$  Since $t$ is the number of years after 1925, the year is approximately 1925 + 54 = 1979. Therefore, the records will be 48.1 seconds or less in 1980 or after.

Solve the Problem R=−0.037t+50.1R=-0.037 t+50.1R=−0.037t+50.1 Can Be Used to Predict the World Record in the Used

Solve the Problem $R=-0.037 t+50.1$ Can Be Used to Predict the World Record in the Used