Soluciones:

A HANDFUL OF DOLLARS: Nothing is missing, of course. The room cost 27 dollars minus 2 dollars, or 25 dollars. The mistake is in adding 2 dollars to 27, instead of subtracting.

THE CHICKEN OR THE EGG? The same three weeks of course, the fact that there are more hens or coops does not shorten the incubation period for hatching eggs.

LIKE LAMBS TO THE SLAUGHTER: Since sheep are renowned for following each other "like sheep", clearly there must be fewer than 99 of them left in the field by now.

POTS N' PANS: Fill the small saucepan and empty its contents into the large pan. The large pan holds now 3 litres and has room for one litre more. Now take the small pan and fill it, and top off the large pan. The amount remaining in the small pan is now exactly 2 litres.

FRIENDLY DASH: Thomas finished in sixth place.