Math practice for 13 year olds - page 349 of 423
Number of problems found: 8458
- Copper plate
Calculate the thickness of the copper plate with a density of 8.7 g/cm³ measuring 1.5 meters and 80 cm, and its weight is 3.65 kg.
- Programmers 3247
The three programmers received a reward of 21,000 euros for their joint work. They received the money according to the work done. The first got 20% less than the second, and the third got 50% more than the first. How much did each of them receive?
- Call of Duty
Game Call of Duty in CTF (Capture the Flag) opposes the British and the Germans, whose bases are 15 km apart. A German soldier stole the British flag and hid it in a secret place between the bases. If the British soldiers set out at a speed of 14 km/h and
- Emptied 3244
The pond is emptied with a sluice in 45 days. When 2/3 of the pond needs to be drained in 15 days, the second sluice gate will also open for 10 days. How many days would the pond be emptied only by a second sluice?
- Tributaries 3243
The water reservoir is filled with one inflow in 30 hours and the other in 40 hours. Both tributaries were opened for some time, then the other tributary closed, and the reservoir filled in 5 hours. How long did the water flow in both tributaries at the s
- Enterprise company
30% of all employees in the enterprise are women. Men are 360 more. How many employees are in the company?
- Regular 3241
The tourist started with a regular step on the road at a speed of 80 steps per minute. After going through 100 steps, his son came to see him and wanted to catch up with him. The son took regular steps as long as his father and moved at 120 steps per minu
- Vertically 3237
A 100 g body is ejected vertically upwards from the surface of the Earth at an initial speed of 30 m/s. Determine the height at which the body rises and its potential energy at the path's highest point.
- Workers 3235
Eight workers in 6 days sweep 2400 m² roads. How many m² will six workers clean in 4 days?
- Motel
Three different dinners, A, B, and C, are served in the motel. Three 20 members went to a motel. Group 1 ordered dinner A 20 members, and their average dinner price in the group was CZK 200. From Group 2, they ordered dinner A: 10 persons, B 10 dinners, a
- Rhombus OWES
OWES is a rhombus, given that OW is 6cm and one diagonal measures 8cm. Find its area?
- Intersection 3229
Intersection of graphs of functions y = 5x-2 and y = -3x-6
- Face of the house
How tall is the roof of a house in the shape of an isosceles triangle with a base length of 8 meters and an arm 5 meters long?
- Working together
One painter painted the nursery in 10 days, the second in 8 days. How many days will the nursery be painted if they work together?
- Children tickets
A ticket to the museum for children costs 10 SKK for adults and 20 SKK. Fifty people came to the museum and paid 700 SKK. How many children were there?
- The glass
The glass has the shape of a cylinder with an inner diameter of 12 cm, and the height from the bottom is 16 cm. The cut skewer can be inserted diagonally into the glass so it does not protrude beyond the edge. What is the largest possible length of the cu
- Preparatory test
Less than 50 pupils go to 9A class. A third of the pupils wrote the preparatory test with a one, a quarter with a two, no one wrote with a three, and nine pupils with a four. How many students from 9A wrote the test with a five?
- Passengers 3221
Express as a ratio: a/ There are 200 boys and 300 girls in the school. b/ The number of chocolates eaten will triple on Nicholas Day. c/ During the holidays, the number of bus passengers decreased by a quarter.
- Probability 3219
In recent years, it has rained 12 days in March. What is the probability that it rained on March 18?
- Sikorsky helicopter
The American concern United Technologies is testing the Sikorsky X2 helicopter, which can fly at a record speed of 464 km/h. How long would it take an F22 Raptor fighter flying at a supersonic speed of 1,856 km/h to catch up with a Sikorsky X2 helicopter
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