Math practice for 13 year olds - page 53 of 435
Number of problems found: 8682
- Temperature 83492
How much heat is needed to turn 1kg of ice at a temperature of -10℃ into steam at a temperature of 100℃?
- Engine power
Calculate the engine power of a truck moving at a constant speed of v= 30 km/h on a road with a 5% gradient when the weight of the truck with the load m= 5000 kg!
- Distinction 83469
In the year's first half, 20% of the 8A class students had honors. At the end of the year, 3 more students joined them, and a total of 32% of the students received the distinction. How many pupils went to 8A?
- Good grades
At school, 10 percent of boys and 15 percent of girls achieve good grades. What percentage of students achieve good grades when 60 percent of girls are in school?
- Accommodates 83454
The dormitory accommodates 173 students in 48 rooms. Some rooms have three beds; some have four beds. If all rooms are fully occupied, determine how many are triples and how many are quadruple rooms.
- Distances 83452
For shorter distances, small train sets are marked with three different letters from the company name run; how many small sets can be marked like this?
- Centimeters 83442
Calculate the length of the arc of a circle and the volume of a circular section if the circle's radius is 8.3 centimeters and the central angle alpha=104 degrees.
- Connecting lines
They are given a square ABCD. The points EFGH are the midpoints of its sides. What part of the area of the square ABCD is the area of the square created in its center by connecting the points AF, BG, CH, and DE?
- Material 83438
Five cars deliver 300 tons of material in 6 days. How many tons of material will 10 cars deliver in 9 days?
- Calculate 83431
In triangle ABC, the size of the exterior angle at vertex C is equal to 126°. The size of the internal angles at vertices A and B are in the ratio 5: 9. Calculate the size of the internal angles α, β, γ of triangle ABC.
- Straight and right
What is the arithmetic mean of straight and right angles?
- Spherical 83427
The bowl, in the shape of part of a spherical surface, has a diameter of 28 cm at the top edge and is 8 cm deep. What is the total volume of the bowl? How much water would you have to pour into the bowl to fill it halfway?
- Hectoliters 83422
A barrel with a volume of 3 hectoliters was rolled into 375 bottles. Some had a volume of 0.7 l, some 1.0 liter. How many were there?
- Sidewalks 83417
The pavers paved 1/8 of the total area of the sidewalk on the first day. On the second day, they paved 20 square meters of pavement. In both two days, they paved 50 square meters of sidewalks. Calculate the total area of the sidewalk.
- Commission 83406
The purchase price of the material is 1000 CZK, and the margin is 35%. What will be the selling price? This is not a trademark or commission.
- Daughter 83402
The mother is 38 years old, and the daughter is 16 years old. When was the mother three times as old as her daughter (how many years ago)?
- Capacity 83398
The hotel has 210 rooms, with 3 beds and 2 beds, and a capacity of 470 places. How much are 2 beds and 3 beds?
- Calculate 83366
Calculate the side a of triangle ABC if we know va=8cm, b=16cm, vb=10cm.
- Representing 83365
30 women work in the police department, representing 60% of the workforce. How many work in the men's department?
- Horizontal 83362
The observer sees the plane at an elevation angle of 35° (angle from the horizontal plane). At that moment, the plane reported an altitude of 4 km. How far from the observer is the place over which the aircraft flies? They circled for hundreds of meters.
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