# Examples for 9th grade - page 3

- Flags

How many different flags can be made from colors red, white, blue, black, yellow, green, purple, gray, orange so that each flag consisted of three different colors? - Seating

How many ways can 7 people sit on 3 numbered chairs (eg seat reservation on the train)? - Football league

In the 2nd football league is 19 teams. How many ways can be filled first, second and third place? - Guests

How many ways can 7 guests sit down on 9 seats standing in a row? - Candies

In the box are 12 candies that look the same. Three of them are filled with nougat, five by nuts, four by cream. At least how many candies must Ivan choose to satisfy itself that the selection of two with the same filling? ? - Stock market

Simon one day decided to invest € 88000 to the stock market. After six months he invested July 5 stock markets fell by 56%. Fortunately for Simon from July 5 5 to October 5 his shares have risen by 39%. Simon is then: ? - Logs

Trunk diameter is 72 cm. Is it possible to inscribe a square prism with side 54 cm? - Series

Andrew wrote this series of numbers: 1,3,7,15, .... n. Which number in the series does not belong? ? - Playing cards

How many possible ways are to shuffle 7 playing cards? - Ace

From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace? - Shelf

How many ways are there to arrange 9 books on a shelf? - Sequence

Write the first 7 members of an arithmetic sequence: a_{1}=8, d=-9. - Logic

A man drinks a barrel of water for 31 days, woman for 58 days, for how many days they drink barrel together? - Trapezoid

Are diagonals in a rectangular trapezoid perpendicular and bisect the angles? - Medals

In how many ways can be divided gold, silver and bronze medal among 18 contestant? - Road

Between cities A and B is route 3 km long of rise average 4‰. Calculate the height difference of cities A and B. - Painter Pavel

Painter Pavel painted the fence for 20 hours and painter Petr the same fence painted for 17 h. How long should take painted the fence together? - Amazing number

An amazing number is name for such even number, the decomposition product of prime numbers has exactly three not necessarily different factors and the sum of all its divisors is equal to twice that number. Find all amazing numbers. - Right Δ

Right triangle has length of one leg 7 cm and length of the hypotenuse 25 cm. Calculate the height of the triangle. - KLMN

In the trapezoid KLMN is given this informations: 1. segments KL and MN are parallel 2. segments KL and KM has same length 3. segments KN, NM and ML has same length. Determine the size of the angle KMN.

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