I was trying to wrap my head around this solution, and the whole idea of a car moving around a level curve, how the friction supplies the centripetal force. But I still can't wrap my head around the idea. So maybe it would help if I walk you through my logic and you can see where I went wrong in my reasoning.
You can deduce from the centripetal force requirement that while moving on a merry-go-round, there has to be some centripetal force that is keeping you moving in the circular pattern. But let's say for a moment that there's no centripetal force acting on me and I'm standing on a merry-go-round. I'll move at a constant velocity in a direction tangent to the center of the circle. "Static friction acting on an object points opposite to the direction in which the object would slide along the other object if static friction didn't exist." So I'm right now at the moment after I started sliding, sliding with a velocity vector that's orthogonal to the centripetal force. If static friction points in the opposite direction, and I'm sliding tangent to the circle, shouldn't it be pointing in the direction opposite the tangent rather than perpendicular to the tangent line?