Maths practice for 14 year olds - page 254 of 375
Number of problems found: 7493
- Last storm - tree
Mr. Radomír had a misfortune during the last storm; a tree fell on his roof in the shape of a regular four-sided pyramid and destroyed it all. The roof has a base edge length of 8m and a side edge length of 15m. How many m² of roofing will he have to buy? - Resistor Ratio in Parallel
If the current flowing through the first resistor is 200 mA and the second is 0.4 A, what will be the ratio of the first and second resistors connected in parallel? - Electric motor power
A current of 2 A at a voltage of 400 V passes through the electric motor. The electric motor is switched on for 0.5 h. What is the power input of the electric motor? - Bulb
A 60 W bulb consumes 0.12 kWh of electricity. How long did she stand light without a break? - The appliance
The appliance has a power input of 2.3 kW. It is connected to the mains voltage of 230 V. What is the current flowing through the appliance? - Water tank
A 288 hectoliter of water was poured into the tank with dimensions of 12 m and, 6 m bottom, and 2 m depth. What part of the volume of the tank water is occupied? Calculate the surface of the tank wetted with water. - Eva and
Eva and Jana have a total of 560 CZK. Eva has a third more than Jana. How much CZK does each have? - Turners
Two turners perform joint work in 3 hours. The first-turner would perform the job himself in 7 hours. How long would the same job last for a second-turner if he worked alone? - Cinema tickets
Cinema sold 180 tickets this Thursday, which is 20%. Monday 14%, Tuesday 6%, Wednesday 9%, Friday 24%, Saturday 12%, and Sunday 15%. How many tickets were sold per week? - Number Increased Percent
The number z increased by 20, which is 40% larger than the number z. Determine the number z. - Grade Percentage Better
There were 21 pupils in the class, and the teacher gave the mark one to 3 pupils, mark two to 5 pupils, mark three to 8 pupils, mark four to 4 pupils, and five to 1 pupils. How many percent of students received a grade better than three? - Nut mixture
A kilogram of one kind of nut is sold for 130 CZK. A kilogram of another type of nuts for 250 CZK. In what proportion are the two kinds of nuts mixed in a mixture whose price is CZK 220 per kilogram? - Rectangle area
The length of a rectangle is x units, and the width is y. Dimensions are increased by 10% and 15%, respectively. What is the ratio of the areas of the old and new rectangle? - Mixture 2
How many liters of water must be added to 7 liters of a 20% solution to obtain a 10% solution? - The train
The train passed the observer in the 20s and passed through a 1500m tunnel in 2 minutes. Calculate the speed (km/h) and train length. - Inscribed circle
Calculate the magnitude of the BAC angle in triangle ABC if it is three times less than the angle BOC, where O is the center of the circle inscribed in triangle ABC. - The coil
How many ropes (a diameter of 8 mm) fit on the coil (threads are wrapped close together)? The coil has the following dimensions: The inner diameter is 400mm. The outside diameter is 800mm. The length of the coil is 470mm. - Mug in Cube Box
A cylindrical mug is packed in a 1-liter cube paper box. The mug is in close contact with all the walls of the cube. What volume is my mug? - The parallelogram
The circumference of the parallelogram is 79.5 m, and its shorter side is half the longer side. What is the length of which side of the parallelogram? - Glass Waste Container Hole
The round hole of the glass waste container has a diameter of 18 cm. Will a four-liter glass pass through this hole? If there are 4 liters of water in the glass, it reaches a height of 20 cm.
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