Raoul makes shell necklaces to sell at a craft fair. The supplies for each necklace cost $3.75. Raoul sells the necklaces for $11.25. What is the percent markup for a shell necklace? will mark brainliest

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)