Like DeltaMac said, you can't compare two processor speeds alone -- there is much, much, much more to the "which is faster?" equation than just clock speed.
In your example, taking clock speed alone, the 2.4 is "faster" than the 2.14. That's to say that the 2.4's clock oscillates at a higher rate than the 2.14. You didn't specify which Core 2 Duo processors those were, so beyond that, it's impossible to say that the 2.4 model is faster/slower than the 2.14.
You need to take into account bus speed (how quick is the path between the processor and RAM?), size of cache (1MB? 2MB? 6MB? 12MB?), type of cache (L1? L2? L3? on-chip? off-chip?) as well as the other components in the computer that the processor is paired with (a 1.8GHz Celeron with an $800 video card will whoop the pants off of a 3.0GHz Core 2 Duo with a $30 graphics card in terms of "graphics" performance).
Your method is "flawed" in the sense that you can't just simply look at the clock speed of a processor and say, "this one is faster than that one." A good rule of thumb is to look at the prices of the processors you're comparing -- typically (but not always), the more expensive one will be "faster" overall (even if it has a lower clock speed!).