# Examples for 9th grade - page 39

- Comparing salaries

Spouses compared salaries. Mrs. Janka found that a 20% higher salary than Mr Jaroslav. Together earned € 1,430. How much they earn each of them? - Workers

9 workers dig a canal 120 meters long for eight hours. For how long would be dig five workers canal 200 meters long? - Determine AP

Determine the difference of the arithmetic progression if a3 = 7, and a4 + a5 = 71 - Blueberries

Miko and Anton have a total of 1,580 blueberries. Miko and Anton have them in the ratio 2: 3. Determine how much each of them has. - Schools

Three schools are attended by 678 pupils. To the first attend 21 students more and to the third 108 fewer students than to second school. How many students attend the schools? - 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. - Distilled water

Sea water contains 5% salt. How many distilled water should be pour to 40 kg of sea water so that the salt content is 2%. How many kilograms of 2% of sea water we get? - Digging

A pit is dug in the shape of a cuboid with dimensions 10mX8mX3m. The earth taken out is spread evenly on a rectangular plot of land with dimensions 40m X 30m. What is the increase in the level of the plot ? - Train expres

At 8.00 strarted from Bratislava to Poprad express Tatry. Cities are distant 340 kilometers. At the same time started from Poprad express Danube to Bratislava. Express Tatry's average speed is 80 km/h, Danube 90 km/h. At what distance from Poprad trains w - Reduce of the volume

Calculate how many % reduce the volume of the cube is we reduced length of each edge by 10%. - Two masons

Two masons built the garage together - it took 18 days. If they worked independently, the other would work 15 days more than the first. For how many days would build the garage each mason himhelp? - Cube 9

What was the original edge length of the cube if after cutting 39 small cubes with an edge length 2 dm left 200 dm^{3}? - Lathe

Calculate the percentage of waste if the cube with 52 cm long edge is lathed to cylinder with a maximum volume. - Crates 2

In 6 crates is 45 kg of apples In 5 crates is equally In 1 in crate is 3 kg more How many kilograms in each crate? - Tank 9

The tank with volume V is filled with one pump for three hours and by second pump for 5 hours. When both pumps will run simultaneously calculate: a) how much of the total volume of the tank is filled in one hour b) for how long is the tank full - Painter

How many euros we will pay for repainting the room shaped cuboid with a length of 4.5 meters, width of 2.5 meters and a height of 3 meters, if for 1 m^{2}with paint we pay € 1.5? - Pytagoriade

Two fifth-graders teams competing in math competitions - in Mathematical Olympiad and Pytagoriade. Of the 33 students competed in at least one of the contest 22 students. Students who competed only in Pytagoriade was twice more than those who just competed - Pyramid a+h

Calculate the volume and surface area of the pyramid on the edge and height a = 26 cm. h = 3 dm. - The farmer field

The field has paralleogram shape with dimensions side a = 65 m and height 429 m. Two and two sides is at angle 65°. Calculate acreage of field in hectares. - Store

Peter paid in store 3 euros more than half the amount that was on arrival to the store. When he leave shop he left 10 euros. How many euros he had upon arrival to the store?

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