How Long to Hit 30?

Hi, so, since I have already hit Gold on my main, I have decided to make a smurf account in order to play ranked matches with my friends. I have purchased a 50 win XP boost. I was wondering, is the fastest way to level my account spamming co-op vs AI for the wins, arams, or normals? Also, how many games should I expect to have to play in order to hit 30? I'd like to hit 30 ASAP. Any help would be appreciated. Thanks!