At the beach mike built a sandcastle that was 2 3/6 feet high if he added a flag that was 2 2/4 feet high what is the total height of his creation answer as a mixed number

Ineed i been stuck on this question since yesterday

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)

What is the rate for one gallon of gasoline