Maths practice for 14 year olds - page 121 of 369
Number of problems found: 7377
- Resistor
Resistor 1, with a resistance of 100 Ohms, and resistor 2, with a resistance of 400 Ohms, are connected side by side in the circuit. The voltage between the resistor terminals is 80V. a) Draw a circuit diagram and write the entered quantities in it b) Fin
- Part-timers 47393
Fifty part-time workers planted 5,200 trees in a forest on a weekend brigade the forest in 9 hours. How many more part-timers do they have to lose next time to plant the same number of trees in eight hours?
- Average speed
The car drove on one section of the highway for half an hour at a speed of 80 km/h. Then he reduced his speed to 60km/h. It went three-quarters of an hour at a speed of 60 km/h. What was the average speed of the car?
- Cone-shaped 47363
We built a cone-shaped shelter with a base diameter of 4 m on the children's playground. Calculate the cone shell if the side of the cone measures 8 m
- Irregular hexagon
There is an irregular hexagon whose sides are the same length. The opposite sides are parallel; their distance is 237, 195, and 193. What is its area?
- Frustrum - volume, area
Calculate the surface and volume of the truncated cone. The radius of the smaller figure is 4 cm, the height of the cone is 4 cm, and the side of the truncated cone is 5 cm.
- Three-quarters of volume
A cylindrical container is three-quarters full with six liters of water. We dip a cube-shaped body into the container, which sinks to the bottom. The length of the edge of the cube is 13 cm. Decide what happens to the sink after the cube is dipped.
- Individual 47281
Two resistors, R1 = 300 ohms and R2 = 600 ohms, are connected next. A voltage of 220V is connected. Determine the total resistance by which we can replace both the electric currents passing through the individual resistors and the electric current passing
- Remaining 47271
Forty percent of all library readers have already paid the annual reader fee, so the remaining 264 have to pay the fee. How many readers does the library have?
- Tic-tac-toe
In how many ways could 9 participants of the school round of five-in-a-row win the first three places?
- Number 47251
From which number 70% is 30?
- Chocolates 47241
Two chocolates and five teas cost a total of 498 CZK. Chocolate is 18 CZK more expensive than tea. How much do one chocolate and one tea cost?
- 25 pupils
Twenty-five pupils attend the school dance group, which is 5 percent of all pupils. The judo class is attended by 20 pupils, a quarter of whom also attend a dance group. How many schoolchildren do not go to a dance or judo group?
- Collection 47221
Mr. Smith has 49 specimens of beetles and spiders in his collection. He needs to remember how many bugs and spiders he has, but he knows he has 324 legs in his collection. How many bugs and spiders does he have in his collection? (Hint: First, figure out
- Confectionery 47211
They want to buy a mixture of candies for the confectionery, which consists of fruit candies at CZK 170/kg and chocolate candies at CZK 240/kg. The mixture should be 20 kg for 212 CZK/kg. How many fruit candies and how many chocolate candies must he buy?
- Pucks
The coach went to buy balls and pucks for his charges. He paid CZK 1,464 for 21 balls and 30 pucks. But then he found out that this amount would not be enough for him, so he bought nine balls and ten pucks for 536 CZK the next day. How much did one ball c
- Sisters 47181
Sisters Hanka and Jana have saved a total of 560 CZK. A third of Hanka's savings equals a quarter of Jana's savings. How much CZK has Hanka saved, and how much has Jana?
- Received 47171
Four boys shared 100 marbles. The second received 20% more than the first, the third received 20 more bullets than the first, and the fourth received 0.8 times more bullets than the first. How many marbles did each boy get?
- Flatbed 47151
How many bricks do they have to lift on a 1.2 m high flatbed if I want to do the work 5.88kj and one brick weighs 5 kg?
- Cross-section 47131
The 5 m long bar has a cross-section of an equilateral triangle with a side of 35 mm. Calculate its volume
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