# Examples for 8th grade - page 56

- Double-track

On double-track express met with a freight train. Express travel at speed 72 km/h, a freight train at speed 36 km/h. After what time period will be from 9 km apart? - Gold coin

Gold coin contains 964 promile pure gold, which is 7.16 g. What is the weight of coin in grams? - High wall

I have a wall 2m high. I need a 15 degree angle (upward) to second wall 4 meters away. How high must the second wall? - Bob and Bobek

At 10h 20min runs Bobek from hat at average speed 12 km/h. At what time must run out Bob at speed 18 km/h to catch him 9 kilometers from the hat? - Concrete box

The concrete box with walls thick 5 cm has the following external dimensions: length 1.4 m, width 38 cm and height 42 cm. How many liters of soil can fit if I fill it to the brim? - President

The country has 5.11 million citizens which 2.12 million are voters. Turnout was 34.4%. President R. F. was elected from 20 candidates for president and won with 38% of votes. Calculate what percentage of the country's citizens voted R.F. as president o - Powers

Express the expression ? as the n-th power of the base 10. - Fraction

For what x expression ? equals zero? - 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? - Box of chocolates

In a box of chocolates was 16 candies. Christopher and Luke they were distributed: a) Christopher had about 4 candies over Luke, b) Christopher had about 6 candies less than Luke, c) Christopher had 3 times more sweet than Luke. How many had each boy can - Chord 4

I need to calculate the circumference of a circle, I know the chord length c=22 cm and the distance from the center d=29 cm chord to the circle. - Siblings

Three siblings had saved up a total of 1,274 CZK. Peter had saved up to 15% more than Jirka and Hanka 10% less than Peter. How much money they saved each one of them? - Regular triangular prism

Calculate the surface area of body of regular triangular prism, when the length of its base edge is 6.5 cm and height 0.2 m. - Tiles

How much you will pay CZK for laying tiles in a square room with a diagonal of 8 m if 1 m^{2}cost CZK 420? - Parallelogram ABCD

The area of parallelogram ABCD is 440 cm^{2}. Points M and N are the midpoints of the sides AB and BC. What is the area of a quadrilateral MBND? - V - slope

The slope of the line whose equation is -3x -9 = 0 is - Basketball

Peter and Franta threw to the basket. Each had 20 attempts. Peter scored thirteen and twelve Franta. Give them success in percentage. - Unknown number 5

I think unknown number. If we enlarge it five times then subtract 3 and result decreases by 75% we get the number by one greater than the number I think. What number am I thinking? - Bonbons 2

Kilo sweets will cost 260 CZK. The first type has a price per 320 kg, the second type 240 CZK per kg. How many kilos of both kinds of sweets need to prepare a 100 kg mixture ? - The tent

The tent shape of a regular quadrilateral pyramid has a base edge length a = 2 m and a height v = 1.8 m. How many m^{2}of cloth we need to make the tent if we have to add 7% of the seams? How many m^{3}of air will be in the tent?

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