Math practice for 13 year olds - page 213 of 413

Number of problems found: 8260

Line length change
The given line is MN with a length of 11 cm. Change its length in the ratio: a) k = 2:1 b) k = 1:2 c) k = 17:11 d) k = 22:33
Train speed calculation
The train ran the distance between stations at a 90 km/h speed in 4 hours. What speed can it take if the journey takes an hour longer according to the new timetable?
In the classroom
There are 30 boys and a few girls in the class. In the six months, 28 boys and all girls benefited, which was 95% of all pupils. How many pupils are there in the classroom?
Square - increase sides
If we increase the length of one pair of opposite sides of the square by 2 cm and the length of the other two sides by 1 cm, we will create a rectangle, the perimeter of which will be 10% larger than the perimeter of the original square. What is the side
Performance improvement percentage
How much percent performance improvement is needed if the work we have planned for five days has to be managed in three days?
Staircase step calculation
The staircase has 36 steps, each 20cm high. How many stairs will the same staircase have if the height of the stairs is 18cm?
Fire tank
1428 hl of water is filled in a block-shaped fire tank with the edges of the base 12 m and 7 m. Calculate the area of water-wetted areas.
Test point threshold
According to school regulations, a student receives an excellent grade if he achieves at least 26 points in a test with a total of 30 points. What is the minimum number of points a student must obtain in a test with a total of 50 points if the same passin
The florist
A consignment of 200 roses arrived at the florist in the morning. She sold more than half of them during the day. She wants to tie bouquets of the remaining roses. One rose will always be left if she ties a bouquet of three, four, five, or six roses. Dete
Checkout waiting time
When only three checkouts are open in a supermarket, people wait in line for an average of 10 minutes. How many minutes will the average waiting time in line be if two more checkouts open?
Outside tangents
Calculate the length of the line segment S₁S₂ if the circles k₁ (S₁, 8 cm) and k2 (S₂,4 cm) touch the outside.
Class student ratio
The class's ratio of boys to girls is 5:7. There are ten boys. How many students are in the class?
Corona again
The population on long island is 7.75 million, and the coronavirus has affected 22,178. What percent of the population is affected? (looking for one case per n people)
Dice roll probability
We roll two dice, red and green. What probability will a more significant number fall on the red dice than on the green?
Kilometers
The scale of the map is 1:100,000. How long is the road, which is 4.7 cm long on the map, really long?
Five-digit divisibility
Find the smallest five-digit number A432B that is divisible by 15.
Marks at school
There are 30 students in the class. Five students in the class had a mark of three or triple at the end of the math certificate, and the other students had a mark of one or two. The average mark in all students' mathematics in the class at the end of the
Drug cure probability
The drug successfully treats the disease in 96% of cases. Your doctor will treat 50 patients with this medicine. What number of cures is most likely?
Candy ratio sharing
Lucy, Jan, and Matthew shared the candy in a ratio of 3:4:5. Matthew got 20 sweets. How many candies did they share?
Roof tile calculation
Three hundred eighty-four tiles are used to cover the roof of 48 m². How many identical tiles are used for a rectangular roof measuring 6 m and 9.5 m?

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