Math practice for 13 year olds - page 169 of 414
Number of problems found: 8280
- Angle of inclination
What percentage of the gradient should be indicated on the mark if the angle of inclination of the road is 6°25'? - Water height
The water tank has the shape of a block. The bottom of the tank is square, with a side length of 3 m. There are 22,500 liters of water in the tank. To what height in meters does the water in the tank reach the specified amount? - Sand pile
Calculate the volume and weight of a pile of cone-shaped sand with a diameter of 8 m and a height of v = 4.5 m; the density of sand is 1500 kg/M cubic. - The aluminum
An aluminium object weighing 0.80 kg at 250 °C is placed in 1.6 kg of water at 23 °C. What is the equilibrium temperature of the system? Assume that heat exchange occurs only between the aluminium object and the water. The specific heat capacity of alumin - The bath
The bath has water with a volume of 220 l and a temperature of 65 °C. Find the mass m2 of water at 15 °C to be poured, so the resulting temperature in the bath will be 40 °C. We neglect the heat exchange between water and the environment. Water - Calculate
Two friends, Mário and Jano, lived on opposite sides of a highway. They decided to find out how wide it was. Mário drew a diagram, based on which they made measurements the next day. They measured the values a = 5 m, b = 5.9 m, and d = 5 m. Calculate the - An average a day
Forest workers planted 96 trees on Monday, 120 on Tuesday, and 61 on Wednesday. How many trees did she plant on the last day of Thursday if she planted an average of 105 trees a day? - Calculation - hemisphere
The roof is shaped like a hemisphere with a diameter of 8 m. Calculate how much m² of roofing is needed to cover the entire top if we count 15% for waste and residues and round the result to tenths of m². Use the constant pi rounded to two decimal places - Diagonals of a prism
The base of the square prism is a rectangle with dimensions of 3 dm and 4 dm. The height of the prism is 1 m. Find out the angle between the body diagonal and the base's diagonal. - Mr. Brown
Mr. Brown invested 15,000 euros in the bank for an annual term deposit. After the first year, he gained 600 euros. What was the annual interest rate of his deposit? - The inflated
The inflated gymnastic ball should have a diameter of 65 cm. How many times do we have to pump air into a full-blown ball with a bicycle inflator to inflate it if the working volume of the inflator is a cylinder with an inner diameter of 2 cm and a height - The granite ball What is the weight of a granite ball with a radius of 60 cm if 1 m³ of granite weighs 2.7 tons?
- The vase
There were roses in the vase. Half were red, a quarter was white, and 12 were yellow. How many roses were in the vase? - MO Z7–I–6 2021
In triangle ABC, point D lies on the AC side and point E on the BC side. The sizes of the angles ABD, BAE, CAE, and CBD are 30°, 60°, 20°, and 30°, respectively. Find the size of the AED angle. - Book page
On the first day, Helen read half of the book. On the second day, half of the rest, and on the third day, she read 35 pages and read the book. How many pages did the book have? - Megapizza
Mega pizza will be divided among 100 people. First gets 1%, 2nd 2% of the remainder, 3rd 3% of the remainder, etc. Last 100th 100% of the remainder. Which person got the biggest portion? - Beam log cutting
Is it possible to cut a beam with a square cross-section with a side length of 30 cm from a log with a diameter of 42 cm? Write the answer as follows: yes, because. ... no, because... - Fish population
The number of fish in a lake decreased by 10% during one year. Last year, 500 fish were found in the lake. What is the fish population this year? - Quadrilateral
The perimeter of a quadrilateral (four-sided plane shape) is 125 cm. How long is the fourth side of the three known sides measure a=12 cm, b=45 cm, and c=30.5 cm? - Online purchase
A ticket for a school performance costs 95 euros. If the ticket is purchased online, there is a discount of 4%. What is the total price of a ticket purchased online?
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