# Examples for 9th grade - page 73

- Resistance

Determine the resistance of the bulb with current 200 mA and is in regular lamp (230V). - Three-digit

How many three-digit natural numbers do not have the number 7? - Bags

The first bag has a weight of 18 kg, the second bag is a one-third lighter than the first and the third bag has three times less the weight of all three bags together. Determine their weights. - Balls

The urn is 8 white and 6 black balls. We pull 4 randomly balls. What is the probability that among them will be two white? - Cuboid enlargement

By how many percent increases the volume of cuboid if its every dimension increases by 30%? - Divisible by 5

How many three-digit odd numbers divisible by 5, which are in place ten's number 3? - Water reservoir

The reservoir shape of a cylinder having a diameter 8 m and a height 2.8 m. The device indicates that the reservoir contains 800 hectoliters of water. Calculate how much % of volume is used. - AP 6

Calculate the first five items of an arithmetic sequence if it is given: a_{2}– a_{3}+ a_{5}= 20 a_{1}+ a_{6}= 38 - Angles in ratio

The size of the angles of the triangle are in ratio x: y = 7: 5 and the angle z is 42° lower than the angle y. Find size of the angles x, y, z. - Four friends

Four friends shared the money. Vasek got 1/4 of the total amount. Tonda received 1/3 of the rest of the money, Joe got a half from the second residue and Jirka left 80. How much money get together? - Body diagonal

Find the cube surface if its body diagonal has a size of 6 cm. - Axial cut

The cone surface is 388.84 cm^{2}, the axial cut is an equilateral triangle. Find the cone volume. - Cube in sphere

The sphere is inscribed cube with edge 8 cm. Find the radius of the sphere. - Reciprocal equation

Determine the root of the equation: 9/x-7/x=1 - Remuneration

Total remuneration for workers is 47 000 CZK. The second worker received 20% more than the first and third 4000 CZK less than a second employee. How many CZK each received? - Linear function

What is the equation of linear function passing through points: a) A (0,3), B (3,0) b) A (-2,-6), B (3,4) - Potatoes 6

The farmer brought potatoes to the market. In the first hour he sold two-fifths of the potatoes brought, in the second hour he sold five-sixth of the remaining potatoes, and in the third hour he had sold the last 40kg of potatoes. How many kg of potatoes d - Garden

The garden has a rectangular shape with lengths of 25 and 40 meters. It has been expanded so that each of its size increased by one fifth. How many square meters increased its acreage? - The ladder

The ladder is 10 m long The ladder is 8 m high How many meters is the distant heel from the wall? - Failure

Drivers of passenger cars have calculated that at a speed of 60 km/h arrives at destination within 40 minutes. After 20 km refrain five minutes due a technical failure. How fast must go the rest of the way to the finish came at the scheduled time?

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