This was on my mind last night.


Some possibilities:
1. He has us beat with a flush (likely), a straight (less likely), or a higher set of jacks (almost never).
2. He is over-playing a loser like 2 pairs or even top pair.
3. He can only win by bluffing.
4. He is betting another loser for some reason.


If #2 through #4 are 5% to 15% each then #1 is 55% to 85%.


If the above isn't too far off then we're getting between 5.5:4.5 and 8.5:1.5, probably closer to the latter.


Having started with $50, we have $27.50 left. The pot has $47.50 from the turn plus another $27.50 from his all-in river bet that has us covered.


As such, the pot odds are 75:27.5 which is between 2.5:1 and 3:1.


We're probably not getting the pot odds we need but we sometimes make the call anyhow.