Jiaming,

I don't know about where they were, but I AM sure that Ranma and his father
were already of the training trip when he and Ryouga met.  Ranma and Ryouga
were in junior high, and since Ranma and his father left for the training
trip when Ranma was 5 or 6, they'd obviously left Nodoka at least 5 years
before.

I hope that helps.
J.L.S.