A question in my workbook is as follows:

A charge of 2 x 10^-6 C is moving with a velocity of 3 x 10^4 m/s at an angle of 30 degrees with a magnetic field of 0.68 T. What is the direction of the force?

Now, I set it up in an XY coordinate system with B (magnetic field) being on the X axis and V (velocity vector) being 30 degrees above the X axis. If you apply the right hand rule to this you get the answer being into the page. This answer is wrong. The right answer is out of the page. Obviously they set it up with V being on the X axis and B being 30 degrees above. Why did they do it this way and not the way I did it?

I realize I am wrong but I would like to know how to set up a problem like this so next time I wouldn't get it wrong.

Thanks guys!