To be (all) set

Context #1

Tom: "We have a big exam today.  Are you ready for it?"
Sam: "Yeah, I studied all night.  I'm all set."

Context #2
Kathy (on the phone): "Hey Jane, I'm on my way and I'll be there in about 10 minutes to pick you up.
Jane: "No problem.  I'm all set and ready to go."

Meaning: "to be (all) set" is an American idiom that is used to express the meaning of being ready and prepared for something.

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