Maths practice for 14 year olds - page 256 of 382

Number of problems found: 7625

Resistors Series Voltage Ratio
If the resistance of the first resistor is 100 ohms and the voltage ratio on the first and second resistors is 2:1. What will be the resistance of the second resistor connected in series?
Sum of squares
The sum of squares above the sides of the rectangular triangle is 900 cm². Calculate the area of the square over the triangle's hypotenuse.
Chasing a Bike Thief
The thief stole Peter's bike and rode it down the road at 25 km/h. Peter's older brother saw it in half a minute and caught up with the thief in 5 minutes on a second bike. How fast must Peter's brother have been driving?
Individual
On a hill behind Terchová, there is a sheepfold where a shepherd lives. He divided his two hundred sheep into 4 groups in a mysterious way: If he had 4 more sheep in the first group, 4 fewer in the second, 4 times more in the third, and 4 times fewer in t
Filling Tank Together
The tank will be filled with the first inlet in 5 hours and the second in 12 hours. How long would it take to fill the tank together?
Tourist Walk and Bus
The tourist traveled 78 km in three hours. For part of the journey, he traveled by bus at an average speed of 30 km/h, and for the rest, he walked at an average speed of 6 km/h. How long did he walk, and how many kilometers did he walk?
Apple price calculation
When you buy 3 kg of apples and 2 kg of oranges, we will pay € 12. When you buy 2 kg of apples and 4 kg of oranges, we pay € 16. How much does 1 kg of apples cost?
Resistance - ohms
If the resistance of the first resistor is 300 ohms and the resistance of the second resistor is 100 ohms. What is the resulting resistance?
Ice cream maker
Ice cream maker Eda has invented a new cone in the shape of a regular four-sided pyramid, in which he will sell his ice cream. The cone will have a lateral edge length of 5 cm and a slant height of 4 cm. In order to mass-produce it in a factory, the dimen
Spiders and Beetles Legs
The boy establishes collections of spiders and beetles. So far, he has only a total of 8. When asked how many beetles he has, he replied: "My entire collection has 54 legs. "How many spiders and how many beetles?
Resistor Current Ratio Parallel
If the resistance ratio of the first and second resistors is 3:1 and the current flowing through the first resistor is 300 mA. What will be the current through the second resistor?
Serial connection
If the voltage on the first resistor is 6 V and the resistance ratio of the first and second resistors is 1:3, what will be the voltage across the second resistor if they are connected in series?
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 8 m and a side edge length of 15 m. How many m² of roofing will he have to bu
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?

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