Are blondes ‘stupid’ or not?

This topic has been going on since the day of Marlin Monroe, whether Blondes are stupid or not. I have heard and read many topics and blog catalogs on this topic. And every time I end up with the result that they are dumb and stupid. But, I think this topic has become so controversial, because most of the celebrities are blonde. And they never completed there schooling because they don’t focus on studies much, because they always had job ready like modeling or acting. And if you have seen, many horror movies the first one to die are blondes.

There is a famous why blondes are stupid joke:
80,000 blondes where gathered for a "Blondes Are Not Stupid" convention. The leader says, "We are all here today to prove to the world that blondes are not stupid. Can I have a volunteer?"

A blonde works her way through the crowd and steps up to the stage.

The leader asks her, "What is 15 plus 15?" After 15 or 20 seconds she says, "18!" Obviously, everyone is a little disappointed. Then, 80,000 blondes start cheering, "Give her another chance! Give her another chance!" The leader says, "Well, since we've gone to the trouble of getting 80,000 of you in one place and we have the world-wide press and global broadcast media here, gee, uh, I guess we can give her another chance."

So he asks, "What is 5 plus 5?" After nearly 30 seconds she eventually says, "90?" The leader is quite perplexed, looks down and just lets out a dejected sigh. Everyone is disheartened. The blonde starts crying and the 80,000 girls begin to yell and wave their hands shouting, "Give her another chance! Give her another chance!"

The leader, unsure whether or not he is doing more harm than good, eventually says, "OK! OK! Just one more chance. What is 2 plus 2?" The girl closes her eyes, and after a whole minute eventually says, "4?". Throughout the stadium, pandemonium breaks out as all 80,000 girls jump to their feet, wave their arms, stomp their feet and scream ... Give her another chance! Give her another chance!
(Source: http://www.tensionnot.com/jokes/blonde_jokes/blondes_are_not_stupid_convention)

There are many pranks like these all over the internet, but are they really stupid. But I think why people refer them as stupid’s, is because they are mostly successful in their life and career (most of them). And most men prefer blonde over brunette, so the thing is that people are jealous of their success. And they want to make them dumb, but whatever the people comment on them they don’t mind it, and they keep moving forward. They may do stupid things we all do it’s not specific, that they do more dazed things and others don’t. I conclude that they are not stupid, and they have right to be thickheaded.