Can someone answer all these please I'm failing this class

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

Compare the cost of the bike trips from the two companies shown.for both the cost in a linear function of the number of days which statements is true

The serenity and the mystic are sail boats. the serenity and the mystic start at the same point and travel away from each other in opposite directions. the serenity travels at 16 mph and the mystic travels at 19 mph. how far apart will they be in 3 hours?