SORRY (Pelm1) THEY GAVE ME $10 EACH ...Igave them $1.00 each change...therefore they outlayed $9.00(thats what they were out of pocket) each = 3x9= 27 plus my $2.00 tip 27 +2=29
You are misstating the equation.
They were out of pocket $9 each and that $27 covered the beer and the tip. The remaining $3 from the initial $30 is back in their pockets as they were each given back $1.
Look at it another way. Lets say they each had $10 in their pockets to begin with. But instead of giving him $30, they gave him $27. The end result is now the same as your scenario - they each have paid $9 and they each have $1 left in their pockets. The $27 paid for the beer ($25) and $2 tip.
