Restaurant confusion

Question

I usually meet with my friend Thomas to discuss engineering mathematics on Saturdays. We agreed to be taking turns when buying lunch (I buy this Saturday he buys the next saturday). On two Saturdays when he was supposed to buy he did not have the money so I bought instead. He was now owing me two meals. But something I couldn't figure out occurred on the next Saturday when he was supposed to buy lunch. This time again he didn't have the money so he suggested that I pay for the meal. He was now going to owe me 3 meals. But I suggested that I give him the money for the meal so that he buys to which he replied "it's the same thing". But it didn't seem to be the same. If a meal is 1 dollar and I bought the third time he was going to owe me 3 meals (3 dollars). If I gave him 1 dollar he was going to owe me 2 meals and 1 dollar but if he used that 1 dollar to buy the meal he was now going to owe me 1 meal and 1 dollar, a total of 2 dollars. How and why is this happening?

Answer 1

• "If I gave him 1 dollar he was going to owe me 2 meals and 1 dollar"

assumes, by your previous analysis, that he uses the dollar to pay for the meal.

So,

• "but if he used that 1 dollar to buy the meal he was now going to owe me 1 meal and 1 dollar"

is clearly false.