In reply to Stanners: You added the pound instead of subtracting it. You have a pound and you owe 2 x £49 = £98 . If you gave back the pound to one parent then you would owe £97.. The cost of the shirt. You may as well say that you owed one parent £49 and the other parent £49. £49 minus £49 = £0. You owe nothing and have a shirt worth £97 and a £1..
By putting the values on the wrong side of the equation doesnt equal the same result.. Sorry I wish it was that easy