Atrain traveled a distance of 255 kilometers. if the trip took 4 hours, what was the train's average speed in meters per second? give your answer to the nearest whole unit.

Acoin bank containing only dimes and quarters has 12 more dimes than quarters. the total value of the coins is $11. how many quarters and dimes are in the coin bank?

The base of a triangle exceeds the height by 9 inches. if the area is 180 square inches, find the length of the base and the height of the triangle.

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)