Maths practice for 14 year olds - page 67 of 376
Number of problems found: 7507
- Pipe repair days
They spent three days repairing the damaged pipe, 115 m long. On the first day, they repaired a quarter of what they did on the second day, and on the third day, they repaired 20m less than on the second day. How many m of pipe did they repair on the firs - Number percentage ratio
The first number is 50% of the second, the second number is 40% of the third, and the third number is 20% of the fourth. The sum of the numbers is 396. Which numbers are these?? - Triangle similarity area
The area of a right-angled triangle KLM with a right angle at the vertex L is 60 mm square, and its hypotenuse k is 10 mm long. Triangles KLM and RST are similar. The similarity ratio is k=2.5. Calculate the area of triangle RST. - Katerina candy division
Katerina has a large package of candies. She ate a quarter and offered a fifth to her friends. She divided the rest of the candies into two equal parts and gave them to her siblings. Brother Michal received 33 candies. How many candies did Katarina have a - Apprentice cost reduction
The apprentice came to his master with an improvement proposal, and with better work organization, we will reduce costs by 45% this year, 30% next year, and 25% the following year. The production won't cost us anything. Has the apprentice received a rewar - Triangle perimeter similarity
Calculate the perimeter of triangle ABC if you know that it is similar to triangle EFG in which e=144 mm, f=164 mm, g=92 mm, and the similarity ratio is 4. Express the result in cm. - Maple model shadow
In the camp, the children made a mock-up of the campsite. In its center was a maple, which had a height of 28 cm on the model. Calculate the height of the maple in the campsite if, in the morning, it casts a shadow 14 m long and its model has a shadow 49 - Quadrilateral perimeter angles
Quadrilateral ABCD has side lengths AB=13cm, CD=3cm, AD=4cm. Angles ACB and ADC are right angles. Calculate the perimeter of quadrilateral ABCD. - Trapezoid cross section
Calculate how many hectoliters of water can fit in a fifty-meter sloped pool; if the smallest depth is 1.2 m and the largest depth is 3 m, the width of the pool is 20 m. - Bear weight percentage
The bear weighed 410 kg at the beginning of winter and lost 10 percent during hibernation. He gained 10 percent of his weight from spring to fall. Find out if the bear's weight was greater at the beginning of winter or autumn by what percentage. - Average of average Three different numbers are given. The average of the average of two smaller numbers and the average of the two larger numbers is equal to the average of all three numbers. The average of the smallest and largest number is 2022. Determine the sum of the t
- Cooker efficiency testing
When testing the effectiveness of an electric cooker with data of 220 V, 1200 W, 1 kg of water at a temperature of 15 degrees Celsius was boiled for 8.5 minutes. Calculate the stove efficiency corresponding to these data - Percentage twelve sixty Calculate what percentage is 12€ of 60€.
- Current wire resistance
The current I = 4A branches into three wires with resistances R1 = 2Ώ, R2 = 5Ώ, R3 = 10Ώ. Calculate the total resistance of the connection and the voltage of the source. How big are the currents in each wire? - Circuit breaker power
The electric circuit breaker automatically switches off the circuit of the 220 V electrical network at a current of 6 A. Determine the maximum power in the protected circuit. - Cooker heat generation An immersion cooker has a resistance of 30 ohms and is connected to a voltage of 120 V. How much heat is generated in 2 hours?
- Bulb consumption hours
A current of 500 mA passed through the filament of a light bulb with a resistance of 400 ohms. What is the consumption of a light bulb in 5 hours? - Cooker plate resistance The immersion cooker plate has data 220 V, 300 W. What is the resistance of the heating wire?
- Iron plate resistance The electric iron plate has written 220 V, 1200 W. What is the resistance of the heating wire?
- Triangle middle crossbar Calculate the length of the middle crossbars in an isosceles triangle if the length of the arm is 52mm and the base height is 48mm
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