Actual interview brainteaser at a top flight shop

The question ask for an exact answer. There is an exact strategy of sizing your bets so that you will always win $100 when you win the game (getting three heads before 3 tails show up). Under this strategy, you will get this result 100% of the time (not that you will win the game 100% of time, but you will get your desired pay off 100% of the time)

 

Also, your probabilities are wrong. Just because the next flip after getting two heads is a tail doesn't mean you lose the game. This is a win: 1101.

 

my career in IB was limited to back office accounting for 15.25/hr

 

I'm not smart enough to know if it's something off the wall like $37.50 so I'll go with 50 bucks a toss.

 

$14.29

 

What to tell me (and everyone here) how you got the answer?

Much like in a real life interview (or a college exam), no credit will be given for an answer without showing work

 

Nope. Remember my hint: you will need figure out the entire bet sizing strategy to arrive at the right answer;

 

1st win $14.29 + 2nd win 2 x $14.29= $28.58 + 3rd win 2 x $28.58= $57.16

$14.29 + $28.58 + $57.16 = $100.03

 

So would the wager amount change depending on circumstance?

 

Did you mean you'll lose on the second TAILS?