Myaaaa, that's a really good effort!
In addition to engkin's comments, I have a couple of suggestions:
1) Change the variable declaration of "passengers, total;" to include the variable type (and an initial value). I'd suggest going with
var
total : single = 0.0;
revenue : single = 0.0;
passengers : integer;
2) Your while statement is slightly messed up. I'd suggest
while (passenger <> 0) do
3) The second last line should use "writeln" not "write".
4) Finally, you might want to consider "cleaning up" your indenting; I'd suggest indenting each level by 2 spaces...
cheers
S.