If you bike for 3 hours at 10 mph and then walk for 1hr at 2mph, what would be your average speed

15 points ! ~ see if you know the answer to both you!

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 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)

Which expression is a perfect cube? a. x8 b. y24 c. m28 d. x64