Is this shop keeper psychic?
SOLUTION
The trick here is to thing of the 10 pounds which is put on the counter. Both men did not do the same thing. Amounts may vary, but, for example, let’s say that a poodle costs £5, a Labrador costs £8, and an Alsation costs £10. The first man must have put a £10 note on the counter, therefore he could have been expecting some change. The second man, on the other hand, put down exact change (perhaps ten £1 coins?) which made it clear that it was the £10 Alsation that he wanted.