Birthday paradox

How large must the group of people be so that the probability that two people have a birthday on the same day of the year is greater than 90%?

Correct answer:

n =  41

Step-by-step explanation:




Did you find an error or inaccuracy? Feel free to write us. Thank you!



avatar







Tips to related online calculators
Our percentage calculator will help you quickly calculate various typical tasks with percentages.
Do you want to convert time units like minutes to seconds?
Would you like to compute count of combinations?

Related math problems and questions:

  • Records
    binomial Records indicate 90% error-free. If 8 records are randomly selected, what is the probability that at least 2 records have no errors?
  • Alarm systems
    cars What is the probability that at least one alarm system will signal the theft of a motor vehicle when the efficiency of the first system is 90% and of the independent second system 80%?
  • Dice
    dices How many times must throw the dice, the probability of throwing at least one six was greater than 90%?
  • Percents from percent
    percent How much is 13% of 20% of 500 greater than 8% of 14% of 200?
  • Sick days
    flu In Canada, there are typically 261 working days per year. If there is a 4.9% chance that an employee takes a sick day. .. what is the probability an employee will use 17 OR MORE sick days in a year?
  • Mastering
    test The student masters the subject matter for the exam in Czech to 98%, from Math to 86% and from Economics to 71%. What is the probability that he will fail from Math and from others will succeed?
  • Geography tests
    test On three 150-point geography tests, you earned grades of 88%, 94%, and 90%. The final test is worth 250 points. What percent do you need on the final to earn 93% of the total points on all tests?
  • Doctors
    doktori The drug successfully treats 90% of cases. Calculate the probability that he will cure at least 18 patients out of 20?
  • The vaccination
    covid19 The vaccination coverage of the population is 80%. Unvaccinated make up 60% of all infected. What percentage are unvaccinated more likely to be infected?
  • Double probability
    dices2 The probability of success of the planned action is 60%. What is the probability that we will achieve success at least once if this action is repeated twice?
  • Utopia Island
    doktori The probability of disease A on the island of Utopia is 40%. The probability of occurrence among the men of this island, which make up 60% of all the population (the rest are women), is 50%. What is the probability of occurrence of A disease among women o
  • Lathe
    sustruh 95% of the components manufactured on the lathe comply with the standard, of which 80% of the components are first-class. How likely can we expect a manufactured part to be first class?
  • The university
    family At a certain university, 25% of students are in the business faculty. Of the students in the business faculty, 66% are males. However, only 52% of all students at the university are male. a. What is the probability that a student selected at random in the
  • Probability - tickets
    zreby What is the probability when you have 25 tickets in 5000 that you not wins the first (one) prize?
  • Family
    stork_bocian What is the probability that a family with 7 childrens have: exactly 6 dívek? 2 dívky and 5 boys? Consider the birth probability of a girl is 48.87% and boy 51.13%.
  • Sales
    tesco From statistics of sales goods, item A buy 51% of people and item B buys 59% of people. What is the probability that from 10 people buy 2 item A and 8 item B?
  • An aircraft
    venn_intersect An aircraft manufacturing company has submitted bids on two separate airline contracts, A and B. The company feels that it has a 70% chance of winning contract A and a 25% chance of winning contract B. Furthermore, it believes that winning contract A is i