Math practice for 13 year olds - page 90 of 422

Number of problems found: 8427

Two brothers 4
Peter is 24 years, and his brother Tom is 6 years. For how long will Peter be three times as Tom?
Natural numbers
Find the number of all natural numbers greater than 200 in which the digits 1, 2, 4, 6, 8 occur at most once and not contains any other digits.
RT area
A right triangle has an area of 54cm². Calculate the sizes of both legs if the shorter leg is 75% of the size of the longer leg.
Isosceles ditch
A ditch with a cross-section in the shape of an isosceles trapezoid with bases of 3 m and 5 m and arms of length 2 m is 2.5 meters deep and 10 meters long. How many cubic meters of soil did they have to excavate when digging it?
A chemist
A chemist recorded the change in temperature of a cooling liquid as −25.5° over a 1.5-minute period. The temperature fell at a constant rate. What was the rate of change in temperature? Enter your answer in the box. °F per minute
Hypotenuse 79904
I have a right triangle, the length of the hypotenuse is c 20, and I only know the side ratio a:b = 2:1. I can't figure out the actual length of the hangers = I'm already an old man, and my brain doesn't work at 100% like it did years ago at school - I co
Right-angled 79894
Mug's handle is in the shape of a right-angled triangle with a hypotenuse of 15.8 cm and a shorter overhang of 5 cm. How tall is a mug?
Three friends
Chad and his two friends are picking blueberries at a local farm. Chad picked 2 1/2 pounds of blueberries, and one of his friends picked 1 3/8 pounds. If they ended up with a total of 5 1/4 pounds, how many pounds did Chad's other friend pick? Express you
Distance 79874
The mast is 190m high and is attached to six ropes which are anchored in the ground at a distance of 20m from the base of the mast. How many meters of rope were needed?
Determine 79864
Determine by how many meters the deviated tower, whose height is 56m, and the top of the tower is located at 55.855m.
Perpendicular 79804
A perpendicular hexagonal prism was created by machining a cube with an edge length of 8 cm. The base of the prism is created from the square wall of the original cube by separating 4 identical right triangles with overhangs of lengths 3cm and 4cm. The he
The amount
The amount of potatoes in kg sold on Monday by three hawkers in the proportion 3:4:5, the least amount sold by one of them is 36kg. What is the amount of potato sold by each of the other two?
School 79774
The school has 275 pupils, and there are fifth more boys than girls. How many girls are there in the school?
Parallelogram - sides
A parallelogram has a perimeter of 30 cm and heights of 10 cm and 6 cm. Find the lengths of its sides.
Determine 79634
There are 12 apples and 10 pears in the basket. Peter has to choose either an apple or a pear from them so that Víra, who chooses 1 apple and 1 pear after him, has the greatest possible choice. Determine what Peter chooses.
Determine 79624
There are 5 roads from city A to city B, 3 from city B to city C, and 4 from city C to city D. Determine the number of paths that go from A to D via B and C.
Four-digit 79614
Determine the number of all four-digit natural numbers in decimal notation in which the digit 0 is not present, and each of the remaining nine numbers occurs at most once.
Determine 79604
In the shoe cabinet, there is one pair each of boots, sandals, tennis shoes, and brown and black ankle boots. Determine how many ways one right shoe and one left shoe can be chosen from among them that do not belong together.
Rectangular 79594
The ratio of the number of liquids to the solid components of the diet in (kg) should be about 7:2. Show in a rectangular coordinate system the dependence of the amount of a solid food component on its total amount.
T-shirts
The team bought white t-shirts for CZK 100/piece and black t-shirts for CZK 80/piece. A total of 50 pieces for 4200 CZK. How many black and white T-shirts did they buy?

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