Time - high school - math problems

  1. Birthday paradox
    holland 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%?
  2. Slow saving in banks
    penize_5 How long will it take to save € 9,000 by depositing € 200 at the beginning of each year at 2% interest?
  3. What is
    exp_growth2 What is the annual percentage increase in the city when the population has tripled in 20 years?
  4. The half life
    exp_growth2 The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. Starting with 145 grams of a radioactive isotope, how much will be left after 3 half-lives?
  5. A particle
    integral_speed A particle moves in a straight line so that its velocity (m/s) at time t seconds is given by v(t) = 3t2-4t-4, t>0. Initially the particle is 8 meters to the right of a fixed origin. After how many seconds is the particle at the origin?
  6. Energy consumption
    elektromer The device is connected to 230V and draws 3.5A current. Power consumption is 1932kJ. How many minutes has this device been in operation?
  7. Working together
    workers Two people will do the work in 12 days. They worked together for 8 days. Then only one worked for 10 days. How many days would each of them do the work if he worked alone?
  8. Compound interest 4
    exp_growth2 3600 dollars is placed in an account with an annual interest rate of 9%. How much will be in the account after 25 years, to the nearest cent?
  9. The tourist
    eq2 The tourist wanted to walk the route 16 km at a specific time. He, therefore, came out at the necessary constant speed. After a 4 km walk, however, he fell unplanned into the lake, where he almost drowned. It took him 20 minutes to get to the shore and re
  10. Corona virus
    covid19 Calculate an estimate of the percentage of GDP (Gross Domestic Product) declined due to the quarantine related to the corona COVID-19 virus that lasts for 2 months, during which time the economic activity is down by 80%.
  11. Self-oscillation period
    lambda The water in the vessel carried by the boy has a self-oscillation period of 0.8 s. What is the size of the boy's movement speed when the length of the boy's step is 60 cm? Give the result in m/s.
  12. Volume of wood
    wood Every year, at the same time, an increase in the volume of wood in the forest is measured. The increase is regularly p% compared to the previous year. If in 10 years the volume of wood has increased by 10%, what is the number p?
  13. Growth of wood
    wood The annual growth of wood in the forest is estimated at 2%. In how many years will make the forest volume double?
  14. Mortage hypo loan
    hypo The Jonáš family decided to buy an older apartment, which cost EUR 30,000. They found EUR 17,000 and took the loan with the bank for the remaining amount. What interest did they receive if they repay this amount for 15 years at EUR 120 per month?
  15. Water current
    river John swims upstream. After a while, he passes the bottle, from that moment he floats for 20 minutes in the same direction. He then turns around and swims back, and from the first meeting with the bottle, he sails 2 kilometers before he reaches the bottle.
  16. Five harvests
    zrno In the seed company, they know that, out of 100 grains of a new variety, they get an average of 2000 grains after harvest. Approximately how many grains do they get out of 100 grains after five harvests?
  17. Pilsen circus
    cirkus The arrival of the circus in Pilsen was seen in the morning at 08:00 by a citizen of the city. He passed this information on 08:15 to three other residents of the city. Each of these three people then informed the other three residents at 08:30, and again
  18. Earnings per share
    usd The table below shows the stock price, earnings per share, and dividends per share for three companies for a recent year: Deere &Co. Price $65.70 earnings per share $4.40 Dividends per share $1.16 Google price $528.33 earnings per share $27.72 Dividends
  19. Pilsen Region
    exp_growth_1 Between 2000 and 2001, 14 per mille of the population decreased in the Pilsen Region. In 2000, the Pilsen Region had 551281 inhabitants. If the declining trend continues the same (i. E. , 14 per mille of inhabitants per year), how many inhabitants will th
  20. A loan
    exp_growth A loan in the amount of $944 is charged simple interest at an annual rate of 8.1%. How much money is owed 14 months after the loan was made?

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