First hand at table.

Full Tilt No-Limit Hold'em, $0.50 BB (6 handed) Converter Tool from (Format: Bet The Pot)

Button ($62.95)
SB ($120.55)
Hero ($50)
UTG ($14.45)
MP ($51.60)
CO ($51.80)

Preflop: Hero is BB with , .
2 folds, CO calls $0.50, 1 fold, SB completes, Hero checks.

Flop: ($1.50) , , (3 players)
SB checks, Hero bets $1.1, CO calls $1.10, SB calls $1.10.

Turn: ($4.80) (3 players)
SB checks, Hero bets $3.25, CO calls $3.25, SB folds.

River: ($11.30) (2 players)
Hero checks, CO bets $10, Hero??

Since you have the I'm leaning towards call, otherwise I'd probably lean towards fold.

There is no way betting the turn is horrible.

Check-folding may be better, but this isn't exactly a board where people love to slowplay jacks (not saying some don't do it, just that it's different from a [Qs][7h] flop). I think turn and river are both close but saying one has a J 90%+ of the time is way way off.

He has a jack like 90% of the time here if not more.