The nucleus of an atom consists of protons and neutrons (no electrons). A nucleus of a carbon-12 isotope contains six protons and six neutrons, while a nitrogen-14 nucleus comprises seven protons and seven neutrons. You perform a nuclear physics experiment in which you bombard nitrogen-14 nuclei with very high speed carbon-12 nuclei emerging from a particle accelerator. As a result of each such collision, the two nuclei disintegrate completely and a mix of different particles are emitted, including electrons, protons, antiprotons (with electric charge -e each), positrons (with charge e each), and various neutral particles (including neutrons and neutrinos). For a particular collision you detect the emitted products and find 15 protons, 2 antiprotons, 6 positrons, and 25 neutral particles. How many electrons are also emitted?