law of committees

What is the cumulative intelligence of a committee ? I've read somewhere that you can compute a good approximation of it starting from the lowest IQ among the participants and subtracting a 10% for each of them.
Recently in the news I've heard that an european commission forbidden to use wood ovens for cooking and I started believing that 1) the EU commission on this must be huge, 2) that there is at least a not very bright person in it, 3) that the 10% of the law should probably be increased.
Luckily enough on the internet I found that to be an "euromyth", so only the law describing the intelligence of news reporters is playing a role here. Of course in the internet you can find everything, both real and fake, hence I can't tell for sure who is lying and who is telling the truth (I'm way too lazy to investigate further and I can't use common sense to see where the truth is especially because of others real regulations that came out of EU commissions: may be that the regulation outlawing good pizza ovens is not real, but for sure it could have been ... and this is the problem).
Probably a good solution would be to have those journalists talk only about the european commissions, and those EU commissions regulating just journalists; we would end up with a better world.