From Garbl's Editorial Style Manual: Q-R
For multiple questions, either use a single question mark at the end of the complete sentence:
Ex: Did Josephine plan the project, manage the budget and supervise the staff?
Or stress each element by breaking up the sentence:
Ex: Did Josephine plan the project? Manage the budget? Supervise the staff?
Also, put only one space after a question mark (and other sentence-ending punctuation).
The question mark replaces the comma normally used when attributing a quotation:
Does that help?
Ex: "Who is going with the reporter?" she asked.