Which inequalities correctly show the relationship between the number 13, -4, and -17

If 3x+8=3x+8 is it one solution or no solution

With number 11 ( show how you got the answer)

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?