Maths practice for 14 year olds - page 39 of 379
Number of problems found: 7575
- Capacity of iron
What was the initial temperature of an iron object weighing 30 kg that, when heated to 39 degrees Celsius, absorbed 3.5 kJ of heat? The specific heat capacity of iron is 450 J/kg/°C. - Calorimetric equation
A 200g aluminum cylinder at 180°C was dropped into 3kg water at 25°C. At what temperature did the resulting temperature stabilize? The specific capacity of water is 4200 J/kg °C, aluminum 896 J/kg °C, - By mass
How much heat must we supply to completely convert potassium weighing 45 kg at a temperature of 22.4 °C into potassium at a temperature of 98 °C? The specific heat of fusion is 25.5 kJ/kg, the melting point is 63.32 °C. The specific heat capacity of potas - Crowbar - lever
How much force must we apply to the end of a 2.4 m long crowbar to lift a door weighing 220 kg, if it stands on the crowbar 35 cm from its end, which is resting on the ground? - In the parking lot 2
There were 12 cars in the parking lot - 5 green, 4 blue, and 3 red. What is the probability that the last car left in the parking lot is blue or green? - Two-kilogram bread
Farmers harvested 3000 kg of rye from one hectare, from which they obtained 2500 kg of flour. 3 kg of flour will make 4 kg of bread. Calculate how many m² of land were used to grow rye, which is needed for 1 two-kilogram loaf of bread. - Borrowed
Mr. Douda borrowed 200,000 SK from the bank at an annual interest rate of 15.4%. He will repay the loan after four years. How many korunas will he have to repay?
- Emptying a tank
A water tank is emptied by one pump in 12 hours, by the second in 9 hours, and by the third in 4 hours. How many hours will it take to empty if all 3 pumps are turned on? - Withholding 83850
An employee receives a net salary of 5000 after a 15% withholding tax. What was the gross salary? - Prepare
From two types of tea priced at 1500,-Sk and 2100,- Sk per kg, 29 kg of a mixture is to be prepared for 1650 per 1 kg. How many kilograms of each type of tea should be mixed? - Chord 24
A chord with length t = r times the square root of two divides a circle with radius r into two circular segments. What is the ratio of the areas of these segments? - Insulating a house
Five workers are working on insulating a house at such a pace that they could finish the job in 18 days. After three days of work, two workers were called away to another construction site. In how many days will the remaining workers finish the job? - Repeatition not allowed
How many four-digit numbers can be formed from the numbers 3 5 8 9 if they are not allowed to be repeated? - Kilometers of the journey
A cyclist traveled 199 km in three days. On the first day, he traveled four times more than on the second day and on the second day, he traveled 7 km less than on the third day. How many kilometers did he travel each day? - Plums - a quarter
How many plums were originally on the bowl if Iva ate a quarter, Jana a fifth, Mišo three-eighths, and then there were 7 left?
- Minutes 83811
How many minutes is 45% of four hours? - Client A bank client had €1,320 deposited in her account throughout the year. At the end of the year, €33 in interest was credited to the account. What interest rate was used to determine the principal?
- Cheaper skis
In Tesco, skis for 9,000 CZK were reduced by 30 percent, in Makro they were reduced by 20 percent first, and after a week by another 10 percent. Where were the skis cheaper in the end? - Maths exam
One-third of all high school students passed the math exam. Five of these students failed the math exam. One-quarter of all students in the high school graduating class passed the math exam. Calculate how many students there were in the high school gradua - Imaginary number If we add 120 to the imaginary number, we get 36 more than if we multiply them by 5. Determine the imaginary number.
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