What is the unit rate of 825 students and 55 teachers

In the diagram, the ratio of ab to ae is (1/2) . what is the ratio of the length of to the length of ?

Evaluate the expression. (9 + 5)(3 + 2)0

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)