Maths practice for 14 year olds - page 286 of 370

Number of problems found: 7384

925 USD
Four classmates saved an annual total of 925 USD. The second saves twice as the first, the third 35 USD more than the second, and the fourth 10 USD less than the first. How does USD save each of them?
Probability 4020
There are numbers from 1 to 20 in the hat. What is the probability that we will pull out from the hat: a / one-digit number b / prime number c / number greater than 11 d / a number divisible by six Thank you
Sufficient 4019
We want to prepare 200g of 64% alcohol. We have a sufficient amount of 80% and 45% alcohol. How many of which will we need?
Equation: 4014
Determine what x equals in the equation: (256^x): 10^-1 = 40
Circumference 4003
Calculate the diagonal length of a rectangle whose length is 3 cm greater than its width and whose circumference is 18 centimeters.
Algebrogram
Solve algebrogram: mama+anna=vari How many solutions are?
Spray - mixture
4 per mille of active ingredient is needed per 6 liters of water to prepare sprays. How many milliliters of active substance do we add to the sprays?
Dividends
The three friends divided the win by the invested money. Karlos got three-eighths, John 320 permille, and the rest got Martin. Who got the most, and which got the least?
Calculate 3987
The diamond has an area of 94.24 square meters and one diagonal of 7.6 cm. Calculate the length of the second diagonal.
Material 3986
There are 1.2 per mille of gold in the rock. How many grams of gold will they get from 45 tons of raw material?
Dimensions 3985
The block of goods has dimensions of 2.5 m, 4.2 m, and a height of 180 cm. It is filled to two-thirds of the volume. How many hectoliters of water are in it? How many m² of the tank is soaked with water?
Active substance
There are 5 ml of active substance in a 600 ml spray. How much is it per mille?
Resistivity 3983
What was the length of an iron wire with an area of 3cm² if its resistance was 15 ohms? Iron (Fe) resistivity is 0.0996 x 10 at -6 Ohm/meter.
Collection 3977
Tomáš brought the collection 20 percent less than Michal. Filip brought half of what Tomas did. Together, they brought 52.8 kg. How much did he bring?
Interest rate
At what annual interest rate would we get an interest of 60 euros on a deposit of € 6,000 for three months?
Numbers 3974
The sum of two numbers is 10,000, and one is four times larger than the other. What are two numbers?
Percentage 3971
Students have classes from 8:00 to 12:30. One 15-minute break and three 10-minute breaks between lessons. What percentage of teaching is breaking?
Diameter 3962
The diameter of the atomic nucleus is 10 to -12cm. How many atoms would fit on a 1 mm line if they could be arranged close together?
Density 3961
The volume of the Sun is 1.4x10 per 18 km cubic, and the weight is 2x10 per 30 kg. What is the average density? (in kg/m cubic)
Direction 3958
In the direction of Hradec Králové, a car left Prague at 8 hours at a 50 km/h speed. At 8 hours and 30 minutes, another car followed him at an average 70 km/h speed. How long will it take to catch up with the first car?

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