Math practice for 13 year olds - page 49 of 422
Number of problems found: 8424
- Hypotenuse of ABC  In a right triangle ABC with hypotenuse c, the hypotenuse a = 6 cm and sin α = 3/5. What is the length of the hypotenuse b? In a right triangle ABC with hypotenuse c, the hypotenuse a = 6 cm and sin α = 3/5. What is the length of the hypotenuse b?
- Four-digit - sum  A four-digit number has a digit sum of 20. The sum of its last two digits is equal to the second digit increased by 5. The sum of the outer digits is equal to the second digit decreased by 3. If we write the digits of this number in reverse order, the num A four-digit number has a digit sum of 20. The sum of its last two digits is equal to the second digit increased by 5. The sum of the outer digits is equal to the second digit decreased by 3. If we write the digits of this number in reverse order, the num
- Probability - target  A target is divided into two zones. The probability that the shooter will hit zone 1 of the target is 21%; that he will hit zone 2 of the target is 48%. What is the probability that the shooter will hit the target? A target is divided into two zones. The probability that the shooter will hit zone 1 of the target is 21%; that he will hit zone 2 of the target is 48%. What is the probability that the shooter will hit the target?
- Mirka 2  Mirka is saving for a bicycle. She already has 336 euros. That is 1/5 more than half the price of a bike. How many euros does a bicycle cost? Mirka is saving for a bicycle. She already has 336 euros. That is 1/5 more than half the price of a bike. How many euros does a bicycle cost?
- Two resistors 5  Two resistors are connected in parallel. The first resistor has a resistance of 2000 ohms and a current of 4 mA flows through it. The second resistor has a resistance of 1600 ohms. 1/Draw a circuit diagram 2/Determine the voltage of the power source. 3/Wh Two resistors are connected in parallel. The first resistor has a resistance of 2000 ohms and a current of 4 mA flows through it. The second resistor has a resistance of 1600 ohms. 1/Draw a circuit diagram 2/Determine the voltage of the power source. 3/Wh
- To the city  A bus leaves for a city 54 km away at an average speed of 15 m/s. 12 minutes after the bus leaves, a motorcycle leaves from the same place to follow it. Calculate the average speed of the motorcycle when it arrives at the destination at the same time as t A bus leaves for a city 54 km away at an average speed of 15 m/s. 12 minutes after the bus leaves, a motorcycle leaves from the same place to follow it. Calculate the average speed of the motorcycle when it arrives at the destination at the same time as t
- Tractor 17  The tractor has an average speed of 2.4 km/h in the first minute of starting, 3.6 km/h in the second and third minutes, and 5.0 km/h in the fourth to sixth minutes. What movement did it make during the first six minutes of driving? Determine the average s The tractor has an average speed of 2.4 km/h in the first minute of starting, 3.6 km/h in the second and third minutes, and 5.0 km/h in the fourth to sixth minutes. What movement did it make during the first six minutes of driving? Determine the average s
- Isosceles  A flower bed has the shape of an isosceles triangle with a base of 25m and sides of 30m. Calculate the maximum number of flowers that can be planted in this bed, assuming that one flower requires about 8 dm² of square area. Round the result to the nearest A flower bed has the shape of an isosceles triangle with a base of 25m and sides of 30m. Calculate the maximum number of flowers that can be planted in this bed, assuming that one flower requires about 8 dm² of square area. Round the result to the nearest
- Laboratory  In the laboratory, twelve liters of 80% prepared 40% alcohol were diluted to a final 70% alcohol. A five-liter barrel of 40% alcohol was available. How much will remain in the barrel of 40% alcohol? In the laboratory, twelve liters of 80% prepared 40% alcohol were diluted to a final 70% alcohol. A five-liter barrel of 40% alcohol was available. How much will remain in the barrel of 40% alcohol?
- Suitcase - rod  The trunk of a car has the shape of a cuboid with sides 1.6m x 1.2m x 0.5m (width, depth, height). Determine the longest thin rod that can be placed on the bottom. The trunk of a car has the shape of a cuboid with sides 1.6m x 1.2m x 0.5m (width, depth, height). Determine the longest thin rod that can be placed on the bottom.
- Equilateral cone  A cup has the shape of an equilateral cone (side “s” is the same size as the diameter of its base - the axial section is an equilateral triangle) It is supposed to hold 0.2 liters of liquid at a level 1 cm below the rim. Calculate its diameter A cup has the shape of an equilateral cone (side “s” is the same size as the diameter of its base - the axial section is an equilateral triangle) It is supposed to hold 0.2 liters of liquid at a level 1 cm below the rim. Calculate its diameter
- Lampshade 3  The lampshade has the shape of a rotating cone shell with a side of 32 cm and a base diameter of 46 cm. Calculate the paper consumption for its production if you assume that the waste will be 6% The lampshade has the shape of a rotating cone shell with a side of 32 cm and a base diameter of 46 cm. Calculate the paper consumption for its production if you assume that the waste will be 6%
- Arbor  Calculate in square meters the area of an arbor whose ground plan is in the shape of a regular hexagon with a side length of 4.5 m. Calculate in square meters the area of an arbor whose ground plan is in the shape of a regular hexagon with a side length of 4.5 m.
- Distance - cities  Determine the actual distance between two cities if their distance on the map is 7.5 cm and the map scale is 1:60,000. Determine the actual distance between two cities if their distance on the map is 7.5 cm and the map scale is 1:60,000.
- Detergent - dilution  The detergent is diluted in a ratio of 1:200. How much detergent do we need if we use 5 liters of water? The detergent is diluted in a ratio of 1:200. How much detergent do we need if we use 5 liters of water?
- Tickets 83964  9 tickets cost 153 CZK. How much do 11 tickets cost? 9 tickets cost 153 CZK. How much do 11 tickets cost?
- Visitors  The first holiday weekend, 1250 visitors came to the swimming pool in Zdice. Sunday was not so nice, so two-thirds of the number of visitors who were at the swimming pool on Saturday came. How many visitors were there on Saturday? The first holiday weekend, 1250 visitors came to the swimming pool in Zdice. Sunday was not so nice, so two-thirds of the number of visitors who were at the swimming pool on Saturday came. How many visitors were there on Saturday?
- Out of 124  Out of 124 students, 68 students went on at least one of the two trips. 82 students did not go on the first trip, and 63 students went on just one trip. How many students went only on the first trip, and how many students went on the second trip? Out of 124 students, 68 students went on at least one of the two trips. 82 students did not go on the first trip, and 63 students went on just one trip. How many students went only on the first trip, and how many students went on the second trip?
- Chord and radius  Calculate the radius of a circle whose chord XY is 8 cm long and whose center is 3 cm from the chord. Calculate the radius of a circle whose chord XY is 8 cm long and whose center is 3 cm from the chord.
- Rhombus 47  A rhombus has a side length of 5 m and a longer diagonal length of 8 m. What is the length of the shorter diagonal of the rhombus? A rhombus has a side length of 5 m and a longer diagonal length of 8 m. What is the length of the shorter diagonal of the rhombus?
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