You basically have it, so long as you know the height of the table.

Knowing the height you can calculate the time that it takes to drop.

Your Vy is initially zero until it goes off the edge.

So the time is given simply by 1/*g*t

^{2} = height of table.

Knowing the time you're rolling in clover because the x distance isd calculated simply by Vx * time.

Not asked but going further if you know the V you know the m*v

^{2}/2 which is going to be equal (if you could ignore

friction and such) to the initial Potential energy of the marble at the height it started rolling down from.