# Examples for 9th grade - page 22

- 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) - Electronics: Resistors in parallel

From relation for calculating the resistance of parallel combination of resistors: ? Calculate the R, if R_{1}= 8kΩ a R_{2}= 18kΩ - 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? - Prize

How many ways can be rewarded 9 participants with the first, second and third prize in a sports competition? - 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? - 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. - Students

In the front row sitting three students and in every other row 11 students more than the previous row. Determine how many students are in the room when the room is 9 lines, and determine how many students are in the seventh row. - Pupils

Four pupils is going via dark hall. Start at one side and have to get to the other side for 17 minutes. They have only one lamp for the trip. The corridor is narrow, they can therefore go up two pupils at a time and go at the slower speed. Each pupil went. - 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? - Father and son

Father is three times older than his son. 12 years ago father was nine times older than the son. How old are father and son? - 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? - Confectionery

The village markets have 8 kinds of sweets, one weighs 15 grams. How many different ways a customer can buy 0.915 kg sweets. - Family

Mom is 42 years old and her daughters 13 and 19. After how many years will mother as old as her daughter together? - Two numbers

We have two numbers. Their sum is 140. One-fifth of the first number is equal to half the second number. Determine those unknown numbers. - Three ints

The sum of three consecutive integers is 2016. What numbers are they? - Shepherd

The shepherd has fewer than 500 sheep; where they can be up to 2, 3, 4, 5, 6 row is always 1 remain, and as can be increased up to 7 rows of the sheep, and it is not increased no ovine. How many sheep has a shepherd? - Classs mean

Class size is 30 students, math was not worse than sign 2. Determine the number of pupils who were sign 1 if the class had a 1.4 sign average. - Ski class

Class attend 30 boys and some number of girls. Ski training was attended by 28 boys and all the girls, which was 95% of all students. How many girls attend this class? How many percent is that? - Cuboids in cube

How many cuboids with dimensions of 6 cm, 8 cm and 12 cm can fit into a cube with side 96 centimeters?

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