Formula required to calculate betting odds/returns

Hi there,

I'm running a virtual betting competition, and need to find out the required formula to calculate A) if a bet won and B) if so, how much the winnings are.

Each competitor can bet on 3 games out of a possible 10, betting on Home Win, Draw, or Away Win.

I have attached a spreadsheet which hopefully clarifies it a bit more.

Many thanks in advance fro you help.