Math practice for 13 year olds - page 296 of 413

Number of problems found: 8260

Cooling liquid
Cooling liquid is diluted with water in a ratio of 3:2 (3 parts by volume of coolant with two volumes of water). How many coolant volumes must be prepared for a total of 0.7 dm³ (liters) of the mixture?
Line segment
Divide a 15 cm line segment into two parts so that their lengths are in a ratio of 2:1. What is the length of each part?
Cube wall
The perimeter of one face of a cube is 120 meters. Calculate the surface area and the space diagonal of this cube.
Kaufland sales-off
As a rule, the goods are approaching the end of consumption in Kaufland three days before the consumption ends 30% off and one day before the consumption ends 50% discounts. Sometimes, however, the seller has been mistaken, and the second discount is alre
Finding the base
Find the unknown base of percent: 12.5 percent of what = 16?
Fuel consumption
The car consumes 6.7 liters per 100km 2. The car consumes 108ml per 1500m. What percentage of more or less gasoline does the 1st car use than the 2nd car to cover the same distance?
Motorcycle and car
A car travels 11000 decimeters per minute, and a motorcycle travels at a speed of 330 meters in 11 seconds. They leave Prague from the same place, and the motorcycle leaves 45 minutes later behind the car. Who will be closer to Vimperek after an hour and
Tree planting
Štěpán is planting trees. If he had planted 12 trees every hour instead of 9 trees, he would have finished 1 hour earlier. How many stems should he plant?
Sum calculation
Calculate the second sum if you know that one sum is -124.6 and the resulting sum is (-200).
Triangular prism
Calculate the volume and surface area of a triangular prism if it is given: a = 6.8 dm (a = base edge length) ha = 4 dm. (ha = base triangle height length) v = 23 dm (v = body height)
Clock path
The minute hand on a clock is 14 cm long. What distance does the tip of the hand travel in 35 minutes?
ICE train
German runways test a new ICE train between Munich and Berlin. The train runs to Berlin at a slow speed of 110 km/h. Back from Berlin goes faster. How quickly did the train have to go on a return trip so that the average train speed for both journeys woul
Outer angles
The outer angle of the triangle ABC at the A vertex is 71°40 ' outer angle at the vertex B is 136°50'. What size is the inner triangle angle at the vertex C?
Cross section
The cross-section ABCD of a swimming pool is a trapezium. Its width is AB=14 meters, the depth at the shallow end is 1.5 meters, and at the deep end is 8 meters. Find the area of the cross-section.
Cube wall
Calculate the cube's diagonal if you know that one wall's surface equals 36 centimeters square. Please also calculate its volume.
Cube surface area
The cube's surface was originally 216 centimeters square. It has shrunk from 216 to 54 centimeters square. Calculate the percent change in the edge of the cube.
Mow the lawn
Dan would mow the lawn in 12 hours and Milada in 16 hours. How long will it take the lawn mow together?
Lines
How many lines can be drawn with 8 points if three points lie on one line and the other any three points do not lie on the same line?
Three-digit
How many three-digit natural numbers do not have the number 7?
Intersect of 10 lines
At how many points do ten lines intersect if no two are parallel?

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