Math practice for 13 year olds - page 300 of 420
Number of problems found: 8400
- Trench
The trench is a four-sided prism. The cross-section has a trapezoidal shape with bases of 4 m and 6 m, and the length of the trench is 30 m. What is the depth of the trench if we dig 60,000 l of soil? - Tree shadow 3
A 2-meter rod casts a shadow 3.2 m long. How high is a tree with a shadow of 14.4 m? - Two boats
The sightseeing boat sailed at 25 km/h. The cruise takes 6 hours. How long does another boat sail at 60 km/h? - Three granaries
Three granaries hold 7,800 metric cents (q) of grain. In the first, 70 tonnes of grain was more than the second, and in the third, it was 120 tonnes less than in the second. How many grains were in each granary? - Pond
Workers will empty a pond with two open floodgates in 20 days. A larger floodgate will empty the whole pond in 30 days. For how long would he be emptied with a smaller floodgate? - Pumping
The tank is filled with a larger pump in 12 hours and with a second pump in 15 hours. For how long does the tank fill when both pumps are switched on at the same time? - Natural numbers
How many natural numbers can we create less than 301 from the number 0,1,2,3,6,7? - Water channel
The cross-section of the water channel is a trapezoid. The bottom width is 19.7 m, the water surface width is 28.5 m, and the side walls have a slope of 67°30' and 61°15'. Calculate how much water flows through the channel in 5 minutes if the water flows - Decagon area
Find the area of a regular decagon if its side is 10 cm in size. - Regular n-gon In a regular n-angle polygon, the internal angle is 144 degrees. Find the number n indicating the number of sides of this polygon.
- Triangle side
I have a circle with a diameter of 6.4 cm. I need to find out the length of the side of an equilateral triangle inscribed in a circle. - Bank account
Peter succumbed to a bank's tempting offer, opened an account, and deposited CZK 1,051 into it. The account bore interest at 1.4%, credited once a year. The fee for maintaining this account was only CZK 140 per year. After seven years, he enjoyed how his - Pyramid surface
There is a regular quadrilateral pyramid with the base edge length a = 3 cm and with the length of the side edge h = 8 cm. Please calculate its surface area and volume. - Stadium area
When the runner goes around the circular stadium five times, he runs 157 km. What area does the stadium occupy? - Well volume
The well has the shape of a cylinder with a base diameter of 1.2 m. From the surface to the surface, it is 4 m, and the water depth is 3.5 m. How many m³ of soil had to be dug when digging the well? How much water (in cubic meters - m3) is in t - Meeting time
At 7 o'clock, a truck drove from Olomouc towards Hradec Králové at an average 40 km/h speed. A passenger car left Hradec Králové, 210 km from Olomouc, in 7 hours 45 minutes with an average speed of 80 km/h. At what time and how far from Olomouc will they - Tree height
Calculate the height of the tree - data - from a distance of 41 m at an angle of 15 degrees. I will see it in its entirety. - Two unknowns
Determine x, y: x + y = 10 x: y = 10 - Trapezoidal prism
Calculate the surface of the quadrilateral prism ABCDA'B'C'D' with the trapezoidal base ABCD. The height of the prism is 12 cm; Trapezoid ABCD has the following dimensions: AB base length is 8 cm, CD base length is 3 cm, BC arm length is 4 cm, and AC diag - Calculate cylinder
A cylinder has a volume V = 120 cm³ and a height v = 4 cm. Calculate the radius and the lateral surface area S.
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