What is a bandpass filter?

Suppose I design a 27KHz active two-valence bandpass filter with a passband of BW=6KHz.
Then I input a 10KHz triangle wave signal, what should the output signal be?
Introduction of filter: www.utmel.com/blog/categories/filters/what-is-filter

Although one or two of us on here are into ham radio, this is a model-flying site, and this has little relevence, as home-build radio is almost non-existant these days.