Question 1062011
It's mu=80 vs. mu NE 80.  "You can average $80/day in tips."  That means it could be on either side or a two way test.

For the next part, reject Ho if |z|>1.28.  That isn't one of the choices, so I would say reject Ho if z>1.28.
The test statistic is z=(82.74-80)/2.81/sqrt (42).
That is 2.74*sqrt(42)/2.81=6.32.  Reject Ho.
This is highly significant at < 0.0001 level