1. ## World Records

If the formula R = -0.037t + 50.1 can be used to predict the world record in the 400-meter dash t years after 1925, for what years will the world records be 48.1 seconds or less?

Do I replace t with 48.1 seconds and solve for R?

2. Originally Posted by sharkman
If the formula R = -0.037t + 50.1 can be used to predict the world record in the 400-meter dash t years after 1925, for what years will the world records be 48.1 seconds or less?

Do I replace t with 48.1 seconds and solve for R?

no replace R with 48.1 and solve for t(which is in years)

3. ## ok...see below

Originally Posted by AwesomeDesiKid
no replace R with 48.1 and solve for t(which is in years)
Thank you very much.

I got t = 54.1 years.

Is this correct?

4. Originally Posted by sharkman
Thank you very much.

I got t = 54.1 years.

Is this correct?
yeah thats rite

5. Strictly speaking, no, it is not right. The problem asked "for what years will the world records be 48.1 seconds or less" and you have not yet answered that question. What you have said is that the record should be down to 48.1 seconds or less 54.1 years after 1925. What years will those be?

(And was it?)