Step-by-step explanation:
first we used the $3 in change to inaccurately subtract $1 from what you owe each of your parents ($50 - $1 = $49) (you're counting backwards!),
and then added to that total debt balance of $98 ($49 I owe mom + $49 I owe dad) the $1 which you kept for yourself to then arrive at the false sum of $99
we should have correctly and consistently added the $3 change back onto the $97-cost of the shirt so that the correct total balance of $100 would then be realized and accounted for as follows:
BEFORE THE PURCHASE OF THE SHIRT
Amount borrowed from mom -- $50
Amount borrowed from dad -- $50
Total borrowed -- $100
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AFTER THE PURCHASE OF THE SHIRT
Cost of shirt -- $ 97
plus $ 3 change:
One dollar to mom -- $ 1
One dollar to dad -- $ 1
One dollar for myself -- $ 1
Total --- $100
