# Examples for 9th grade - page 21

- Hockey players

After we cycle five hockey players sit down. What is the probability that the two best scorers of this crew will sit next to each other? - Sequence

Write the first 7 members of these sequence: a_{1}= -4 a_{2}= 10 a_{n+2}= a_{n+1}-1 a_{n} - Balance

The rod are 1.7 m long hanging weights 2 kg and 12 kg on ends. Where are centre of rod (distance from weight 2 kg) to be in balance? - Pool

If water flows into the pool by two inlets, fill the whole for 9 hours. First inlet filled pool 8 hour longer than second. How long pool is filled with two inlets separately? - Water level

How high reaches the water in the cylindrical barell with a diameter of 12 cm if there is a liter of water? Express in cm with an accuracy of 1 decimal place. - School

School attend 792 children, boys and girls ratio is 4:5. How many more girls go to school (than boys)? - Kids

How many different ways can sit 5 boys and 5 girls in line, if girls want to sit on the edge? - River

From the observatory 15 m high and 39 m from the river bank, river width appears in the visual angle φ = 22°. Calculate width of the river. - Short cut

Imagine that you are going to the friend. That path has a length 330 meters. Then turn doprava and go another 840 meters and you are at a friend's. The question is how much the journey will be shorter if you go direct across the field? - Diofant equation

In the set of integers (Z) solve the equation: ? Write result with integer parameter ? (parameter t = ...-2,-1,0,1,2,3... if equation has infinitely many solutions) - Donuts

In the dining room at one table sit Thomas, Filip and Martin. Together they eat 36 donuts. How many donuts eaten everyone, when Filip ate twice as much as Thomas and Martin even half over Filip? - Smallest internal angle

Calculate what size has the smallest internal angle of the triangle if values of angles α:β:γ = 3:4:8 - Cube and water

How many liters of water can fit into a cube with an edge length of 0.11 m? - Price reduction

Price of camera is 800 USD on sale its price reduced to 423 USD. Calculate the percentage reduction in the price of the camera. - Map

On the tourist map at a scale of 1 : 100000 is distance between two points along a straight road 5.4 cm. How long travels this distance on a bike at 23 km/h? Time express in minutes. - Average height

In a class are 34 students. The average height of students is 165 cm. What will be the average height of students in the classroom when two pupils tall 176 cm and 170 cm moved from this school/class? - Distance runner

Distance runner already climbed three fifths of the total route. Thus passed 90 km. How many km he have to stop? How long is his route? - Rope slack

Between two streets 20 m away give the lamp, which is in the middle and hanging 60 cm bellow the taut rope. Can be done with 20.5 meters rope? - Chess

How many different ways can initiate a game of chess (first pass)? - Children

Less than 20 children is played various games on the yard. They can create a pairs, triso and quartets. How many children were in the yard when Annie came to them?

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