Another math problem 2

I once lent 50 dollars to a man and 50 dollars to a woman. And they paid in the following way:

Man
On day one paid 20 owed 30
On day Two paid 15 owed 15
On day Three paid 10 owed 5
On day Four paid 5 owed 0
Result 50 50

Logical isn’t it. As you can see the result of the paid and owed columns are the same

But the woman
On day one paid 20 owed 30
On day Two paid 18 owed 12
On day Three paid 3 owed 9
On day Four paid 9 owed 0
Result 50 51

Why is there a difference in the result?, as you can see the sum of the owed column in the woman’s payment does not match the owed amount, why is there an extra dollar?

Originally posted by Superman
I once lent 50 dollars to a man and 50 dollars to a woman. And they paid in the following way:

Man
On day one paid 20 owed 30
On day Two paid 15 owed 15
On day Three paid 10 owed 5
On day Four paid 5 owed 0
Result 50 50

Logical isn’t it. As you ...[text shortened]... owed column in the woman’s payment does not match the owed amount, why is there an extra dollar?

Originally posted by AThousandYoung
Because there's no reason to sum the individual "owed" numbers. The man's "owed" numbers coincidentally (or were chosen to) add up to 50, but that doesn't mean it should occur with any pay schedule. A more extreme example:

Bob pays 1 owes 49
Bob pays 1 owes 48

Already, his total "owed" sum is 97.