In Bitcoin terms, simultaneous answers occur frequently, but at the end of the day there can only be one winning answer. When multiple simultaneous answers are presented that are equal to or less than the target number, the Bitcoin network will decide by a simple majority--51%--which miner to honor. Typically, it is the miner who has done the most work, i.e. verifies the most transactions. The losing block then becomes an "orphan block." 
Remember that "Bitcoin exchange" and "Bitcoin wallet" need not be the same. Bitcoin exchanges are kind of like foreign exchange markets – places where you can trade Bitcoin for a fiat currency, say, BTC for USD and vice versa (in U.S. for example). While exchanges offer wallet capabilities to users, it’s not their primary business. Since wallets need to be kept safe and secure, exchanges do not encourage storing of Bitcoins for higher amounts or long periods of time. Hence, it is best to transfer your Bitcoins to a secure wallet. Security must be your top priority while opting for a Bitcoin wallet; always opt for the one with multi-signature facility.

In September 2015, the establishment of the peer-reviewed academic journal Ledger (ISSN 2379-5980) was announced. It covers studies of cryptocurrencies and related technologies, and is published by the University of Pittsburgh.[231] The journal encourages authors to digitally sign a file hash of submitted papers, which will then be timestamped into the bitcoin blockchain. Authors are also asked to include a personal bitcoin address in the first page of their papers.[232][233]
People, don’t be fooled by the apparent advantages and usages of Blockchain technology or Bitcoin, it’s what you don’t know that is destructive to you personally and to society in general. It is merely another way to control you through information, to hack into your private lives and the only ones that truly benefit from this technology are the global wealthy elite, the greedy, materialistic oligarchs of global chaos and conflict. Bitcoin is virtual money, it doesn’t really exist except on the computer!
The price of bitcoins has gone through cycles of appreciation and depreciation referred to by some as bubbles and busts.[153] In 2011, the value of one bitcoin rapidly rose from about US$0.30 to US$32 before returning to US$2.[154] In the latter half of 2012 and during the 2012–13 Cypriot financial crisis, the bitcoin price began to rise,[155] reaching a high of US$266 on 10 April 2013, before crashing to around US$50.[156] On 29 November 2013, the cost of one bitcoin rose to a peak of US$1,242.[157] In 2014, the price fell sharply, and as of April remained depressed at little more than half 2013 prices. As of August 2014 it was under US$600.[158] During their time as bitcoin developers, Gavin Andresen[159] and Mike Hearn[160] warned that bubbles may occur.

Blockchain is the underlying technology behind cryptocurrencies like Bitcoin. Unlike physical currency, digital cash and cryptocurrencies come with a very real problem called Double-Spending. Let me explain what that is. When I email you a picture of my cat, I’m sending you a copy and not my original picture. However, when I need to send you money online, as much as I would love to send you a copy of it, it’s a bad idea if I really do that! With Bitcoin, there was a risk that the holder could just send copies of the same bitcoin token in different transactions, leading to “Double-Spending”.
Bitcoin is a perfect case study for the possible inefficiencies of blockchain. Bitcoin’s “proof of work” system takes about ten minutes to add a new block to the blockchain. At that rate, it’s estimated that the blockchain network can only manage seven transactions per second (TPS). Although other cryptocurrencies like Ethereum (20 TPS) and Bitcoin Cash (60 TPS) perform better than bitcoin, they are still limited by blockchain. Legacy brand Visa, for context, can process 24,000 TPS.
In Bitcoin, it’s like every organic food store has someone out front, offering free samples. Also, there’s a library everywhere you look, but only a few of those libraries have any good information. The largest traders would benefit a great deal if everyone just jumped blindly into Bitcoin, investing large chunks of their life savings in the process. That would be just fine by them, but it’s unlikely to happen. More likely, people are going to get involved with Bitcoin either by necessity, by chance or because someone was willing to give them a few bitcoins to get started with.
One of the Bitcoin blockchain's most innovative aspects is how it incentivizes nodes to participate in the intensive consensus-building process by randomly rewarding one node with a fixed bounty (currently 12.5 BTC) every time a new block is settled and committed to the chain. This accumulation of Bitcoin in exchange for participation is called "mining" and is how new currency is added to the total system afloat.

The Bank for International Settlements summarized several criticisms of bitcoin in Chapter V of their 2018 annual report. The criticisms include the lack of stability in bitcoin's price, the high energy consumption, high and variable transactions costs, the poor security and fraud at cryptocurrency exchanges, vulnerability to debasement (from forking), and the influence of miners.[185][186][187]
To lower the costs, bitcoin miners have set up in places like Iceland where geothermal energy is cheap and cooling Arctic air is free.[201] Bitcoin miners are known to use hydroelectric power in Tibet, Quebec, Washington (state), and Austria to reduce electricity costs.[200][202][203][204] Miners are attracted to suppliers such as Hydro Quebec that have energy surpluses.[205] According to a University of Cambridge study, much of bitcoin mining is done in China, where electricity is subsidized by the government.[206][207]

Blockchain is the underlying technology for digital currency like Bitcoin, Litecoin, and Ethereum and other digital properties. The technology records every transaction of a digital currency or property in a database or digital ledger. It also copies and distributes the database to a network of computers to validate each transaction. This decentralizes, secures, and publicizes each digital currency’s or property’s database of transactions.

That one google doc’s guy is sort of off in his definition of blockchain to dita…as that is what that scenario is. I worked with a system named Centralpoint also allows for a IFTTT (If this then that) approach to building your own logic engine (or rules engine), which to use Blockchain venacular would be considered Smart Contracts. Examples of this would be when to send someone an email report (business intelligence) or when to trigger a new record entry into your CRM.
The bitcoin blockchain is a public ledger that records bitcoin transactions.[67] It is implemented as a chain of blocks, each block containing a hash of the previous block up to the genesis block[a] of the chain. A network of communicating nodes running bitcoin software maintains the blockchain.[31]:215–219 Transactions of the form payer X sends Y bitcoins to payee Z are broadcast to this network using readily available software applications.