In a survey conducted over a group of people, it was found that 65% of them have a Facebook account, 40% of them have an Instagram account and 25% of them have a Twitter account. It was also concluded that 20% have an account on both Facebook and Instagram, 12% have an account on both Instagram and Twitter and 14% have an account on both Facebook and Twitter. If 8% of the people had an account on all the three websites, what percentage of the people do not have an account on any of the three websites?

In a survey conducted over a group of people, it was found that 65% of them have a Facebook account, 40% of them have an Instagram account and 25% of them have a Twitter account. It was also concluded that 20% have an account on both Facebook and Instagram, 12% have an account on both Instagram and Twitter and 14% have an account on both Facebook and Twitter. If 8% of the people had an account on all the three websites, what percentage of the people do not have an account on any of the three websites? Correct Answer 8%

Let,

⇒ n(F) = Percentage of people that have a Facebook account = 65%

⇒ n(I) = Percentage of people that have a Instagram account = 40%

⇒ n(T) = Percentage of people that have a Twitter account = 25%

Also,

⇒ n(F ∩ I) = Percentage of people that have an account on both Facebook & Instagram = 20%

⇒ n(F ∩ T) = Percentage of people that have an account on both Instagram & Twitter = 12%

⇒ n(I ∩ T) = Percentage of people that have an account on both Facebook & Twitter = 14%

⇒ n(F ∩ I ∩ T) = Percentage of people that have an account on all three websites = 8%

∵ According to the basic formula of Venn diagram for three elements,

⇒ n(A ∪ B ∪ C) = n(A) + n(B) + n(C) – n(A ∩ B) – n(B ∩ C) – n(A ∩ C) + n(A ∩ B ∩ C)

⇒ n(F ∪ I ∪ T) = 65 + 40 + 25 – 20 – 12 – 14 + 8 = 92%

⇒ Percentage of people having an account on the three websites = 92%

∴ Percentage of people that do not have an account on any of the three websites = 100 – 92 = 8%

Related Questions

The question given below consists of a statement, followed by three arguments I, II and III. You have to decide which of the arguments is/are ‘strong’ arguments is/are ‘weak’ arguments and accordingly choose your answer from the alternatives given below each question. Statement: For users, Facebook's revelation of a data breach that gave attackers access to 50 million accounts raises an important question: What happens next? For the owners of the affected accounts, and of another 40 million that Facebook considered at risk, the first order of business may be a simple one: sign back into the app. Facebook logged everyone out of all 90 million accounts in order to reset digital keys the hackers had stolen - keys normally used to keep users logged in, but which could also give outsiders full control of the compromised accounts.  Which of the following points do not capture the negligence of Facebook in the most appropriate manner? Arguments: I. What Facebook knows so far is that hackers got access to the 50 million accounts by exploiting three distinct bugs in Facebook's code that allowed them to steal those digital keys, technically known as ‘access tokens’. The company says it has fixed the bugs.  II. The hack is the latest setback for Facebook during a tumultuous year of security problems and privacy issues . So far, though, none of these issues have significantly shaken the confidence of the company's 2 billion global users.  III. One of the bugs was more than a year old and affected how the ‘View As’ feature interacted with Facebook's video uploading feature for posting ‘happy birthday’ messages. But it wasn't until mid-September that Facebook noticed an uptick in unusual activity, and not until this week that it learned of the attack.