@absmalls,
The hillbilly from Louseeezeeanna who first told me that riddle said even Einstein couldn't figure it out...
It is only a matter of perception, or rather, of misdirection... 3 times 9 is 27, but what she has given them is 30 minus 2 which is 28... From the perspective of those who paid 30, 30 minus the 3 they got back is 27, but what they actually paid, 25 plus the 3 is 28, plus the 2 is 30... What they think they paid has nothing to do with the reality of the situation... It is a matter of the obvious truth versus the actual truth...