Math practice for 13 year olds - page 371 of 423
Number of problems found: 8452
- Mass
The thickness of a metallic tube is 1cm, and its outer radius is 11cm. Find the mass of such a 1m long tube if the metal density is 7.5g per cubic cm. - Land areas
Two land areas are 244 m². The first parcel is 40 m² less than twice the second one. What is the acreage of each parcel? - Internal angles
The ABCD is an isosceles trapezoid, which holds: |AB| = 2 |BC| = 2 |CD| = 2 |DA|: On the BC side is a K point such that |BK| = 2 |KC|, on its side CD is the point L such that |CL| = 2 |LD|, and on its side DA, the point M is such that | DM | = 2 |MA|. Det - Coal storage
The coal storage distribution received coal shipment within three days. On the first day, distribute a third of the shipments, on the second day of two-fifths of the rest, and on the third day, 300 tons of coal. How many tons of coal were distributed firs - Similarity
ABC is a triangle wherein a = 4 cm, b = 6 cm, c = 8 cm. Is it similar to the triangle DEF: d = 3 cm, e = 4.5 cm, f = 6 cm? If so, determine the ratio of similarity. - Rectangle
The width of the rectangle is 65% of its length, and its perimeter is 132 cm. Determine the dimensions of the rectangle. - Addends
Number 118 is divided into two addends, so the first addend is 69, greater than 75% of the second addend. - Mr. Happy
Mr. Happy planted 36.6 meters of square garden grass; It's a third of the garden, more than half of the garden. What is the square area of this garden? - Three friends
Peter is eight times older than Rado, and Rado is three times younger than Joseph. Together they have 120 years. Determine how many are each of them. - Pumps 5
Five pumps pumped in 3 hours 1800 hl of water. How many hectoliters of water were pumped by four equally powerful pumps in 6 hours? - Work at plant
The handyman vowed to do repair work at the plant for 25 days. However, work had to be shortened, so he sought help. Together, they made all the corrections for 13 1/3 days. How long would the work take the helper himself? - Hexagons
There is a square ABCD, a square EFGD, and a rectangle HIJD, points JG lie on the side CD, while DJ is less than DG, and points HE lie on the side DA, while DH is less than DE. We also know that DJ is equal to GC. Hexagon ABCGFE has a perimeter of 96 cm, - Unoccupied swallows
The swallows flew in and sat on the benches, one swallow on each bench, while one swallow did not miss an empty bench. If two swallows sat on each bench, one bench would remain unoccupied. How many swallows were there, and how many benches? - Probability - tickets
What is the probability when you have 25 tickets in 5000 that you do not win the first (one) prize? - MO - triangles
On the AB and AC sides of the ABC triangle lies successive points E and F, and on segment EF lie point D. The EF and BC lines are parallel. It is true this ratio FD:DE = AE:EB = 2:1. The area of the ABC triangle is 27 hectares, and line segments EF, AD, a - Chord circle
The circle to the (S, r = 8 cm) are different points A, B connected segment /AB/ = 12 cm. AB mark the middle of S'. Calculate |SS'|. Make the sketch. - Painters 4
One painter will do the job for 12 days. After a 4 1/3 day, he comes second to help him complete work together for eight days. How long would work the second painter himself? - Hiker and cyclist
At 7 PM hiker started at 6 km/h to hike. After three hrs. later started on the same trip cyclist at a speed of 15 km/h. After an hour of driving a flat tire and takes him half hour to correct the defect. At what time catch up cyclist with the hiker? - Triangular pyramid
Calculate the volume and surface area of a regular triangular pyramid with a height equal to the base edge, which is 10 cm long. - Keyboards keys
Michael had small keys on the shelf, which you can see in the picture. Their tones were marked on the white keys. Little Clara found the keys. As she took them off the shelf, they fell out of her hand, and all the white keys spilled out. So that the broth
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