How do you weigh your head? The brain teasers that tell if you are you smart enough to work at Google

It has long been considered one of the best companies to work for, but do you have what it takes to work for Google?
It may take a sharp mind, as an author claims that the search giant requires its applicants to answer perplexing trivia questions and riddles.
Author William Poundstone claims to have unlocked the secret of acing an interview at Google and other top technology firms, and is revealing his secrets in a new book.
In Are You Smart Enough to Work at Google, Poundstone describes several interview questions that he claims that his tips will increase an applicant's chances of not only getting hired by Google, but anywhere.
He told ABC News: 'HR departments are running scared, asking themselves, "How can we make sure our questions have predictive power for how well someone will do on the job?"'
Poundstone outlines several of the brain teasers that are said to be used by actual Google interviewers, from 'How much toilet paper would you need to cover Texas' to 'Can you swim faster in water or syrup?'
He told ABC News that whether a job applicant can answer the question or not, it’s best to ask follow up questions to show that you recognise what is being asked.
Google would not comment on Poundstone's book, but some are quick to point out that the interview questions that have been circulating the web for several years are works of fiction.