Math practice for 13 year olds - page 47 of 434
Number of problems found: 8665
- Dependent variables
A printer prints k sheets in n seconds ( k, n ϵ N ). Express the number of sheets that the printer prints in 5 minutes in terms of k and n.
- Parking 84175
There are 96 cars in the parking lot. There are 24 fewer dark cars than light cars. How many light cars are there in the parking lot?
- A year ago
A year ago, Jano was twice as old as Lenka. In five years, Jano will be half as old as Lenka. How old is Lenka?
- Ratio 52
The ratio of the surface area of a cube to its volume is 2:1.Calculate: a) the length of the edge of the cube in cm b) the volume of the cube in cm³ c) the volume of the cube in cm2
- Princesses
Princesses Anna and Elsa are picking strawberries, which have ripened in huge quantities after a long winter. Anna can pick one bed in 120 minutes, and Elsa is faster and can finish an equally large bed in 15 minutes. How many minutes would it take the ro
- MO Z7 2025
Adela and Susan ate plums. On the first day, Adela ate three quarters of what Susan ate that day. On the second day, Susan ate three halves of what Adela ate that day. Together, they ate 31 plums over the two days, and each girl ate the entire number of p
- Originally 84156
The pants cost 9.90 euros, which is 90% of the original price. How much did the pants cost originally?
- Heating 2
The heating coil of the stove has an electrical resistance of 80 ohms and is connected to an electrical voltage of 230V. Calculate the electrical energy consumed in a year (365 days) if it is switched on for 2 hours a day. How much will we pay for the ene
- Tank - fuel prices
I have a car with a 50l tank. My task is to find out the price of a full tank of fuel by weighted average at the end of the year. In December, 30l of fuel was filled - 37.50 CZK, and in November 40l - 38.40 CZK. What is the price per 1 liter and the value
- Table - tablecloth
Mrs. Vránová has a square table with a side length of 110 centimeters. She wants to have a square tablecloth sewn on it so that its corners extend beyond the edges of the table by 25 centimeters. What dimensions should the tablecloth have?
- Left-handed
There are 100 people in a room, 99% of whom are left-handed. How many left-handed people must leave the room to reduce this proportion to 98%?
- Peter 27
Peter earned twice as much as Jano on his part-time job. Jano earned 50 euros less than Peter. How much did each of them earn?
- Irregular
Calculate the area and perimeter of the garden that was created from a rectangular plot measuring 10 by 20 meters after transferring one corner measuring 6 by 7 meters. The separated rectangular plot has parallel sides to the main plot. Did the perimeter
- Thinking unknown n
I am thinking of a number. If I subtract 14 from it and multiply by 6, I get the number 210. What is the number I am thinking of?
- Spiral - iron
An electric iron is connected to a 230 V voltage source. Its heating coil has an electrical resistance of 100 ohms. Calculate the power of the iron and the electric current flowing through the coil.
- Tank 28
The tank fills in 120 hours. When irrigated, it empties in 10 days. At what time will it fill with simultaneous irrigation?
- Oranges and apples
Mr. Novák bought 5 times more oranges than apples. One orange cost 8 CZK and one apple costs 12 CZK. He paid 156 CZK in total. How many oranges and apples did he buy?
- Asphalt
A tennis court can have a grass, asphalt, or clay surface. Singles are played on a court 23.78 m long and 8.23 m wide. For doubles, a strip 1.37 m wide is added on both longer sides. How many m² is a tennis court for doubles larger than for singles?
- Railing 3
A railing in a museum is filled with 18 glass plates in the shape of a parallelogram with a side length of 40cm and a corresponding height of 65cm. How many m² of glass were needed to produce these fillings?
- Expanding
A problem has spread here - money printing. The ECB claims it aims to maintain a price level with 2% inflation. But for the last three years in a row, annual inflation has been 6%, 7% and 9%.
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