22 in the sb, multiway pre but unsure about implied odds

1 - (48/50)*(47/49)*(46/48) = 0.11755102, or 11.76% approx, or 1 in 8.5 approx, or 1:7.5 approx.

You're right. These are the odds of flopping a set or better, which is really what we are interested into. The ones I quoted are the odds of flopping exactly a set.

Note: actually 1 - (48/50)*(47/49)*(46/48) = 0.882449 and these are the odds of x not being on the flop when we hold xx. 1-0.882449=11.76% are then the odds that at least one x is on the flop, which includes xyy and xxy flops which give you a boat or quads.