Assume that for each miner, the probability of successfully solving the hash-puzzle is p. Also assume that there are n miners in the system.

Assume that for each miner, the probability of successfully

solving the hash-puzzle is p. Also assume that there are n miners in the system. Also,

assume once a block has been mined, the new block reaches every node instantaneously

(no network latency). So, all miners can start mining the next block simultaneously.

Suppose Bob - the merchant wants to have a policy that orders placed to him will

ship within x minutes of the transaction of payment placed by the buyer to Bob. What

value of x must Bob choose so that he can have 99% confidence that 6 blocks will be

found in the next x minutes?