Math practice for 13 year olds - page 380 of 423
Number of problems found: 8443
- Circle sector
The circular sector with a central angle 160° has an area 452 cm². Calculate its radius r. - Troops - soldiers
Food stocks will last 20 soldiers during the four-day training. If four soldiers become sick, how many days could they extend training? - Hurry - rush
I will travel from the school to the bus stop at an average speed of 7 km/h for 24 minutes. How fast do I need to go if I need to get there in 17 minutes? - Floating floor
In the new building, a floating floor worker is considered in each room. Thirty minutes lay 9 m² of the floor. How long did three workers lay the floor in four rooms with a total area of 90 m²? - Tea blend
Tea blends are made from two kinds of tea. In standard tea, the mixture is two teas in a ratio of 1:3, and 40 g costs 42 CZK. In the premium tea mixture, weighing two teas in the 1:1 and 50 grams ratio costs 60 CZK. How much cost 10 grams of a more expens - Class pairs
In a class of 34 students, including 14 boys and 20 girls. How many couples (heterosexual, boy-girl) can we create? By what formula? - Digits A, B, C
For the various digits A, B, and C is true: the square root of the BC is equal to the A, and the sum B+C is equal to A. Calculate A + 2B + 3C. (BC is a two-digit number, not a product). - Miraculous tree
The miraculous tree grows so fast that the first day increases its height by half the total height of the second day by the third, the third day by a quarter, etc. How many times will it increase its height after 6 days? - The rod
The rod is painted in four colors. 55% of the bar is painted blue or green, 0.2 of the rod, 1/8 is brown, and the remaining 45 cm is white. How long is the rod? - Water well
A drilled well has a depth of 20 meters and a radius of 0.1 meters. How many liters of water can fit into the well? - Following 1859
Solve the following linear equation in R: 4/10X + 2/10X + 1/6X + 1/10X + 400 = X - Polygon 42
Which polygon has 42 more diagonals than sides? - Concrete pipe
How much will it cost to cover a 6 m long concrete pipe with an outer radius of 1.5 m and an inner radius of 0.8 meters if one m² paint costs 24 €? - Circular lawn
Around a circular lawn area is a 2 m wide sidewalk. The outer edge of the sidewalk is a curb whose width is 2 m. The Curbstone and the inner side of the sidewalk together form concentric circles. Calculate the area of the circular lawn, and the result rou - Rhombus base
Calculate the volume and surface area of prisms whose base is a rhombus with diagonals u1 = 17 cm and u2 = 14 cm. The prism height is twice the base edge length. - For thinkings
The glass cube dives into the aquarium, which has a length of 25 cm, a width of 20 cm, and a height of 30 cm. Aquarium water rises by 2 cm. a) What is the volume of a cube? b) How many centimeters measure its edge? - Two cars
From A town started two cars to town B. The first begins at 7:00 at an average speed of 60 km per hour. The second car starts at 10:00 at an average speed of 100 km per hour. The first car will not stay in B, and on the way back, meet the second car halfw - Hollow sphere
The hollow steel sphere floats on the water, plunged into half its volume. Determine the outer radius of the sphere and wall thickness if you know that the weight of the sphere is 0.5 kg and the density of steel is 7850 kg/m³ - Blackjack TU160
Bomber Tupolev TU160 started at 9:00 from the airport and flew at an average speed of 1850 km/h toward Airfield B, a distance of 3500 km. After evaluating the danger from the airport, B started at 9:45 B towards A fighter MIG 29 at an average speed of 230 - Volume from surface area
What is the volume of the cube whose surface area is 96 cm²?
Do you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.
