Dan has some marbles ellie has twice as many marbles as dan frank has 15 marbles dan, ellie and frank have a total of 63 marbles a) how many marbles has does dan have. b)write the ratio of dans marbles to ellie's marbles in its simplest form.

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)