Math practice for 13 year olds - page 91 of 435
Number of problems found: 8682
- 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?
- Evaluate expression
What is: the sum of negative four and one-half times n plus the quantity one-fourth plus one and three-fourths times n minus three-eighths?
- Supermarket 79504
The supermarket reduced the original price of the skis by 20% in January. At the beginning of February, they reduced the new price by another 29%. By what percentage were the skis' costs lower than the original price in February?
- A test 3
A test of five light bulbs showed that they burned for the following lengths of time (in days): 17 2/3, 19 1/4, 20 1/2, 21, and 18 3/4. For how many days, on average, did the light bulbs burn?
- Expressed 79474
The length of the cube's edge in cm is expressed as a natural number. Its volume is greater than 100 and less than 200. Calculate the surface area of the cube.
- Divisible 79464
The teacher wrote a number less than 50,000 on the board. The first student said: This number is divisible by 2 The second student said: This number is divisible by 3 And so on, down to the last one who claimed it was divisible by 13. Two in a row lied. W
- Yesterday 79344
Petr played Minecraft for 2 hours yesterday. Pavel played 10% longer. How many minutes did Pavel play?
- Blackboard 79334
The biology teacher, Carrot, randomly called the students to the blackboard. There were 25 pupils in the class, and Mr. Carrot called Ludek, Silva, and Mathias. What percentage of the total number of students was called today?
- The angles 3
The angles in a triangle are in the ratio of 3:4:5. Work out the size of each angle.
- Blueberries 79284
Lenka, Jane, and Michael collected blueberries in the ratio of 3:4:2. Lenka collected 4.5 liters of blueberries. How many blueberries did Jane and Michael collect?
- Completely 79274
Kitchen cabinets are sold in widths of 80 cm, 60 cm, and 40 cm. Which assembly can we choose if we have a wall 3.5 m long and we want to completely fill it with an assembly that also includes a dishwasher, the width of which is 60 cm, and the stove is 50
- Pasture 79214
I need to find out the number of bulls in the third period. In the first period, 12 bulls grazed on 3 and 1/3 ha for 4 weeks. In the second period, 21 bulls graze on 10 ha for 9 weeks. How many bulls in the third period graze for 24ha and 18 weeks? The pa
- Owl A,B,C
Owl a gives a hoot every 7 minutes. Owl b gives a hoot every 9 minutes. Owl c gives a hoot every 5 minutes except when he has heard owl a or b give a hoot within the previous 2.5 minutes. If this happens, owl c doesn't give a hoot. If all three owls give
- Calculate 79144
The circle's radius is r=8.9 cm, and the chord AB of this circle has a length of 16 cm. Calculate the distance of chord AB from the center of the circle.
- Difference 79094
Trapezoid, gamma angle=121°, alpha angle=2 thirds of delta angle. Calculate the angle difference alpha, beta
- Value of a expression
Find the value 5(11)-10²-15+20
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