If Roy Halloday wins I get $10, so what's the best play? In a mathematical view point in the long term?

If I'm bettin $20




I was thinking of taking +1.5, and then you only loose to a blow out and even then you get 50% back.



Thanks guys!!!


Tell me if it's smart or too conservative.

'Cuz I was thinking what if I did the opposite -1.5, more swings, but bigger upside?