Maths practice for 14 year olds - page 65 of 379
Number of problems found: 7575
- Resistances 80706
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?
- Automatically 80704
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.
- Resistance 80703
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?
- Consumption 80702
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?
- Resistance 80699
The immersion cooker plate has data 220 V, 300 W. What is the resistance of the heating wire?
- Resistance 80698
The electric iron plate has written 220 V, 1200 W. What is the resistance of the heating wire?
- Crossbars 80697
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
- Sweaters 80695
Out of 400 sweaters, 5% are second quality, and the rest are first quality. How many sweaters are of first and second quality?
- Single-digit 80674
There are cows, ducks, and geese on the farm. They have a total of 126 legs. Ducks are 3 more than houses. And there are 20 cows. If we count all the animals, we have to divide them by the number three, and we should get a single-digit number.
- Strawberries - shop
Mom and grandma went shopping at the market. Mom bought 2 kg of strawberries and 3 liters of blueberries and paid 250 CZK. Grandma bought 1 kg more strawberries and 0.5 l fewer blueberries than mom and paid 45 CZK more than her. How much did 1 kg of straw
- Grandchildren 80639
The average age of the grandfather, grandmother, and their five grandchildren is 26 years. The average age of the grandchildren themselves is 7 years. Grandma is a year younger than grandpa. How old is grandma?
- Calculate 80636
Calculate the distance of a chord 19 cm long from the center of a circle with a diameter of 28 cm.
- Two-thirds 80635
The car traveled the first third of the track with a constant speed of v1, the next two-thirds of the way at a constant speed of v2=72km/h, and the average speed of v=36km/h. Find v1.
- Acceleration 80626
The car stopped at an initial speed of 90 km/h on a track of 62.5 m. What was its acceleration, and how long did it take to brake the car?
- Participated 80621
Three 9th-grade classes participated in the paper collection competition. The company bought 1 kilogram of paper for €0.12, and the school received €174 thanks to their hard work. Calculate how many kg of paper 9A collected if you know that she collected
- Difference 80618
A regular hexagon is described and inscribed in a circle. The difference between its areas is 8√3. Find the circle's radius.
- Roland
Roland repairs and sells broken furniture. He pays $300 for a gaming chair and sells it for $408. What is his percent markup?
- In the desert
A man wondering in the desert walks 5.7 miles in the direction S 26° W. He then turns 90° and walks 9 miles in the direction N 49° W. At that time, how far is he from his starting point, and what is his bearing from his starting point?
- Inflated
By the time a man decided to buy a house, the cost had inflated by around 8% to £182,000. What was the approximate price before inflation?
- Tristan
Tristan normally wrestles at 80 pounds. He wants to add enough weight to move into the 84-pound division. What percent of his current body weight must he add?
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