Travia question

[wills]

Ok so I borrow £100 from Dom and I spend it all on shopping. I then borrow £50 from Chris, In total I have borrowed £150.
I use £30 of the £50 I borrow from Chris to give to Dom and the remainder £20 from the £50 I borrow from Chris I spend on food.
I now owe Dom £70 and Chris £50.
In total £70 plus £50 equals £120 plus the £20 I spend on food equals £140.
Where has the remainder £10 gone?

 

[Unknown008]

Ok so I borrow £100 from Dom and I spend it all on shopping. I then borrow £50 from Chris, In total I have borrowed £150.
I use £30 of the £50 I borrow from Chris to give to Dom and the remainder £20 from the £50 I borrow from Chris I spend on food.
I now owe Dom £70 and Chris £50.
In total £70 plus £50 equals £120 plus the £20 I spend on food equals £140.
Where has the remainder £10 gone?

You just shouldn't count 'imaginary' money. Those £70 and £50 are money you owe and don't really exist.

What exists is:
£100 you spent on shopping.
£20 you spent on food.
£30 you gave back to Dom.

Which make a total of £150.

 

[daon2]

At the end you are in debt £120, there is no missing money, that is how much you spent and gave the rest back. I'm not sure why the "solution" adds the £20 that you spent to your debt. Makes no sense. They might as well add the £100 and say, "why is there £240?"