# Examples for secondary school students - page 47

- Concentration

How many grams of 65% and 50% acid is to be mixed to give 240 g acid with a concentration of 60%? - Piano

If Suzan practicing 10 minutes at Monday; every other day she wants to practice 2 times as much as the previous day, how many hours and minutes will have to practice on Friday? - Gasoline

35 l of gasoline is to be divided into four canisters so that in the third canister was 5 l less than the first canister, the fourth canister 10 l more than in the third canister and the second canister half what in the first canister. How many liters of. - Task of the year

Determine the number of integers from 1 to 10^{6}with ending four digits 2006. - Freezer

The freezer has the shape of a cuboid with internal dimensions of 12 cm, 10 cm, 30 cm. A layer of ice of 23 mm thick was formed on the inner walls (and on the opening) of the freezer. How many liters of water will drain if we dispose the freezer? - Sphere vs cube

How many percent of the surface of a sphere of radius 12 cm is the surface of a cube inscribed in this sphere? - Ladder slope

What is the slope of a ladder 6.2 m long and 5.12 m in height. - Three friends

Divide 570 euros to three friends so that first will get 50 euros less than the second and third twice more than the first. How many euros will get everyone? - Nuts

Peter has 49 nuts. Walnuts have 3 more than hazelnuts and hazelnut 2 over almonds. Determine the number of wallnuts, almonds and hazelnuts. - Numbers at ratio

The two numbers are in a ratio 3:2. If we each increase by 5 would be at a ratio of 4:3. What is the sum of original numbers? - Crystal water

The chemist wanted to check the content of water of crystallization of chromic potassium alum K_{2}SO_{4}* Cr_{2}(SO_{4}) 3 * 24 H_{2}O, which was a long time in the laboratory. From 96.8 g of K_{2}SO_{4}* Cr_{2}(SO_{4}) 3 * 24 H_{2}O prepared 979 cm^{3}solution of base. S - Normal Distribution

At one college, GPA's are normally distributed with a mean of 3.1 and a standard deviation of 0.4. What percentage of students at the college have a GPA between 2.7 and 3.5? - Lines

How many lines can be draw with 8 points, if three points lie on one line and the other any three points do not lie on the same line? - Billiard balls

A layer of ivory billiard balls of radius 6.35 cm is in the form of a square. The balls are arranged so that each ball is tangent to every one adjacent to it. In the spaces between sets of 4 adjacent balls other balls rest, equal in size to the original. T - Pentagon

Calculate the length of side, circumference and area of a regular pentagon, which is inscribed in a circle with radius r = 6 cm. - Quatrefoil

Calculate area of the quatrefoil which is inscribed in a square with side 6 cm. - Variations

Determine the number of items when the count of variations of fourth class without repeating is 42 times larger than the count of variations of third class without repetition. - 3s prism

It is given a regular perpendicular triangular prism with a height 19.0 cm and a base edge length 7.1 cm. Calculate the volume of the prism. - Candies

If Alena give Lenka 3 candy will still have 1 more candy. If Lenka give Alena 1 candy Alena will hame twice more than Lenka. How many candies have each of them? - Truncated cone 5

The height of a cone 7 cm and the length of side is 10 cm and the lower radius is 3cm. What could the possible answer for the upper radius of truncated cone?

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