Question

Julia finds that the data in the table can be modeled by the function y = 5(4)x.

A 2-column table with 5 rows. The first column is labeled time (minutes) with entries 0, 1, 2, 4, 8. The second column is labeled distance (feet) with entries 5, 20, 80, 320, 640.
Which statement about Julia’s finding is true?

Julia is correct because the distance starts at 5 feet and increases by a factor of 4.
Julia is correct because the function is true for (0, 5) and (1, 20).
Julia is not correct because the function is not true for the point (2, 80).
Julia is not correct because the distance does not increase by a constant factor each minute.

Answer 1

Answer: Julia is not correct because the distance does not increase by a constant factor each minute.

Reason: y = 5·4^x gives y(4) = 5·4^4 = 1280, but the table has 320 at t = 4, so the model fails. The factor per minute is not constant across the table.