Maths practice for 14 year olds - page 51 of 378
Number of problems found: 7551
- Purchased 82340
The company secretary bought stamps worth CZK 20 and CZK 15. The total number of purchased stamps is 120, and the secretary paid a total of 2265 CZK. How many stamps worth 15 CZK did she buy?
- Landscape 82339
Soňa is sitting on the train, looking out the window, and what she doesn't see is that the landscape runs backward at a constant speed of 160 km/h, and on the side track, the train is seemingly backing up at a constant speed of 40 km/h. Sonia stops and wo
- Subtract 82333
I think of three numbers; when I add them, I get 16; when I subtract the third from the sum of the first two numbers, I get 10; when I subtract the second from the sum of the first and third numbers, I get 8. Which numbers do I think?
- Repeated 82330
How many 5-digit numbers can we create from the number 1,2,3,4,5 if the one's place is to have the number 5? (digits must not be repeated.)
- Numbers 82320
5% of the first and 4% of the second numbers add up to 46. 4% of the first and 5% of the second numbers add up to 44. What are the numbers?
- Thermal energy
From the formula for calculating thermal energy Q=m*c*t, express t and calculate by how many °C 2kg of water must be heated to increase its energy by 126kJ
- Deciliters 82303
Juraj had 1 liter of pure orange juice in the bottle. He drained 2 deciliters of it and replaced it with water. What is the ratio of orange juice to water in the bottle now?
- Basis 82283
What is the basis if 40% of the base is €320?
- Calculate 82282
Calculate the sizes of the interior angles in the triangle whose vertices are the points marked by the numbers 1, 5, and 8 on the clock face.
- Boiler 82273
The ship and boiler are 49 years old. The ship is twice as old as the boiler was when the ship was as old as the boiler is now. How old is the ship?
- Five-digit 82257
Determine the number of all five-digit natural numbers in which every two digits are different in decimal notation.
- One-twentieth 82239
Peter and Honzo decided to build the building as quickly as possible. They built one-twentieth of the building in ten minutes. After 20 minutes, three more friends joined. Everyone was building at the same pace. How many minutes did it take to build the s
- Capacity 82231
There were 60 people in the stadium, which was 30% of capacity. How many people can fit in the stadium?
- Acceleration 82217
The car has a speed of 5 m/s and accelerates to 35 m/s in 12 seconds. Calculate the acceleration of the car at a speed of 34.5 m/s.
- Trapezoid 82216
Given is an isosceles trapezoid ABCD with bases 10 cm and 14 cm. The height of the trapezoid is 6 cm. Determine the interior angles of the trapezoid.
- Dance party
At the dance party, the organizer discovered that 168 different dance pairs could be formed from girls and boys. How many boys are there at the dance if there are 12 girls?
- Excavators 82208
Two excavators dig a pit in 12 days. How much shorter will this job take if 8 excavators dig the hole? In 3 or 9 days?
- Semi-skimmed 82206
The dairy produces semi-skimmed milk (with 1.5% fat content) by skimming part of the fat from full-fat milk (with 4% fat content). 1 ton of semi-skimmed milk is produced from how many kilograms of fat milk?
- Beginning 82198
At the end of the year, the lady had 360,009 CZK in her account with added interest. What was the amount at the beginning of the year if the interest rate was 10.5% pa?
- Sun and shadow
The pole is stuck vertically into the ground. The protruding length is 1m. What is the length of the shadow cast when the sun is just 50° above the horizon?
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