Can someone help me ASAP??? Four friends are in a swimming race. each Swim as many laps as they can and then tag the next one until they complete 50 laps the first swimmer completes 4/10 of the race. The 2ed completes 8 laps and the third summer complete 22% of the race how many laps will the last member have to swim to complete the race

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)

I’m stuck on this equation, anyone got the answer?

Pls never taught i’m really confused and i rlly need