Can you tell me the answer? E = ?

If 10 men take 18 days to mow 60 acres of grass, how long will 15 men take to mow 80 acres?

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)

Credit card a offers an introductory apr of 3.4% for the first three months and standard apr of 15.7% thereafter,