Qwiss you started with £50. Won an extra £40 from the bookies so a total of £90 in your hand. You give £50 to Liverpool fan and you have £40 in your hand from the £50 you started with so a £10 loss, no? Am I bugging out?
Edit: But like I said, I'm not too familiar with betting at the bookies so I am very well be calculating things wrong.