Yes, manxman - the 4 has been removed from the sequence ("out four")

Great solve, Denis - as you spotted, the crux is picking that initial weighing - 2 of one colour, one each of the others.

Denis

Hank you, hank you...am now leaving the building

Can we have the answer to #5 please

I'm thinking it's about 9.5 feet, or the circumference of the roller.

Length of Cue's pool table in basement?

Ah yes, diameter x Pi. I'll have to learn math all over again to answer these questions.

Cue - afraid not. I had to check this one for mysrlf

Answer tomorrrow if no takers

2*Circumference=2*pi*d=18.85

Yes, manxman!

Goes contrary to what you think is the obvious (9.2), but if you imagine the centre of the rollers being stationary, then the slab goes 9.4 one way, and the ground goes 9.4 the other way. So the plank moves approx 18.4 in relation to the ground.

Yes, exactly what I thought.