I don't have that much time

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

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?

What is 140 squared pleas me i am dumb