Un sure on this if someone could answer would be great !

Kayla has a $500 budget for the school party. she paid $150 for the decorations. food will cost $5.50 per student. what inequality represents the number of students, s, that can attend the party?

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)

3.4a=57.8 what is the the value of a