Here is another hand for discussion, a slight modification of an actual hand someone sent to me. Again, the goal is not to get the right answer, but to think about some interesting situations. Please feel free to post some ideas even if you might change your mind later.
50-30-20 Mid-stakes SNG
No relevant reads.
Blinds 120/240
CO: 4500
BTN: 3120
SB: 480 (360 after posting)
BB (Hero): 5400
Preflop:
fold, BTN minraises to 480, SB calls 360 (all-in), BB calls 240 with 9♠ 5♠.
Flop (1440, 3 players): Q♠ 5♥ 4♠
BB checks, BTN bets 1440 (1200 behind), BB ???
1) Is the BB's preflop call ok?
2) What is the range for the BTN on the flop?
3) How much equity does 9♠ 5♠ have against that range?
4) How much equity does the BB need to call on the flop?