Alison, Hector, and Myles had a challenge to see who could run the farthest in a month. Alison ran 21 miles. Hector ran 5 times as many miles as Myles, and Myles ran 2 times as many miles as Alison. How many miles did Hector run?

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)