Imagine if Jackie helped Donna out with a school project. I'm sure Jackie would need a bit of focusing because her ego would take over, but once she got into the project, she might be more passionate about it than Donna.
(Of course, this all depends on what version of Jackie we're talking about. The show gives us several versions of each other character throughout the series. Most of them have things in common, but there are also definite differences among them.)