Most Helpful Guy
Off course guys like smart girls heck i dated a girl who had a 4.0 while i had a 3.84. there's nothing unnatractive about it unless you're one of those guys who feels weak infront of girls who just happen to be smartet, stronger or have more skill at certain things.
Most Helpful Girl
Guys don't really care about how smart you are. Most of them only care about your personality. Don't try to act dumb just because 'all guys' chase dumb girls. It's going to make you look dumb AND fake. Those 'dumb' girls probably has a really charming personality and maybe a look to go with it, so all guys are swooning after her/them.