I got the following question which I can't figure out:
Alice, Bob, Carol, David and Eve are the five major bitcoin miners. They have each invested a million dollars in specialized equipment for bitcoin mining and have driven every other miner to look for other opportunities, i.e. every block in the bitcoin block chain is mined by one of them. The first four are happy just making money off of mining and save their money in bitcoin banks. Eve is willing to invest every bitcoin she makes in buying more mining equipment. Recall that the probability that a miner succeeds in mining a block is the number of hashes that the miner computes divided by the total number of hashes that the whole network computes. Assume that on average a dollar buys enough mining equipment to compute 225 SHA-256 hashes per second, that the mining fee for each block is 12.5 bitcoins and that each bitcoin is worth 500 dollars. What is the expected time required for Eve to be able to decide for every bitcoin transaction whether it is entered in the block chain, and therefore accepted, or not.
Can anyone explain how do I need to calculate this?