senegal.. from cairn half -yearly presentation, page-11

Explaining my post - two wells, each with probability P of success, probability of both being dusters is (1-P)*(1-P).
In for P=.25, chance of both being dusters is .5625, so 43.75% chance of at least one of them being successful.

The difference between buying a betting slip and a load of shares, is that the return on a betting slip is all or nothing, whereas the return or loss on shares is a sliding scale. If you bought a slip at 3/1 on success for one of the wells, your return would be $4 or nothing. Also, your 3/1 bet is on one specific well, where a punt on FAR is at least one of the wells coming in, but also something happening in L6. A bet on a well compared to buying shares in the driller is like comparing apples to oranges.