for any maths boffins

if somebody backs a 4 way dead heat at for £100 at 10/1

i realise that this will be settled as a 1/4 stake times odds

ie £25 @ 10/1 =£250 + £25 stake money back = £275 return so in fact taking into account your intial stake the equivalent of a  7/4 winner.
  this leads me on to

if i laid D Villa at 1.95 to be top scorer for £100 and there was a resulting 4 way tie the person backing Villa  would only return £48.75 who would get the residual £51.25