Trong sơ đồ sau, một con kiến đang di chuyển từ a sang b. Nếu kiến chỉ được phép di chuyển sang phải lên trên một dòng lưới dài, có bao nhiêu con đường khác nhau có từ a đến b
sơ đồ đâu
an ant is crowling from point a to point b using the staircase.how many meters will it crawl to reach point b
A,B,C,D,A+C,B+C,A+D,B+D represent 8 diffirent natural numbers from 1 to 8. If A is the largest number in the number from 1 to 8.Find A
How many natural numbers are there between 100 and 999 that unit-digit and tens-digit equal hundreds-digit ?
Combinatorics
21. 15 students join a competition. Only top 5 students can be promoted to next round. How many different way(s) of promotion advance is / are there?
Different way: Cách khác nhau.
22. It is known that there are 8 classes of grade 5 in a primary school. At least how many students are there in grade 5 to ensure there exist 41 students in the same class?
At least: Ít nhất; Ensure: Chắc chắn; Exist: Tồn tại.
23. Choose 3 digits from 1, 2, 3, 4, 6, 8 and 0 to form 3-digit numbers. How many even number(s) greater than 300 is / are there? (The repetition of digits is not allowed)
Digit: Chữ số; 3-digit number: Số có 3 chữ số; Even number: Số chẵn; Greater than: Lớn hơn; Repetition of digits is not allowed: Các chữ số không được lặp lại.
24. A flight of stairs has 10 steps. Peter can go up for 1 step, 2 steps or 3 steps each time. How many way(s) is / are there for Peter to go up the stairs?
Step: Bước; Way: Cách.
25. Numbers are drawn from 80 integers 20 to 99. At least how many number(s) is / are drawn at random to ensure that there are two numbers whose sum is 85?
Integer: Số nguyên; At least: Ít nhất; Random: Ngẫu nhiên; Ensure: Chắc chắn; Sum: Tổng.
~ End of Paper ~
Combinatorics
21. 15 students join a competition. Only top 5 students can be promoted to next round. How many different way(s) of promotion advance is / are there?
Different way: Cách khác nhau.
22. It is known that there are 8 classes of grade 5 in a primary school. At least how many students are there in grade 5 to ensure there exist 41 students in the same class?
At least: Ít nhất; Ensure: Chắc chắn; Exist: Tồn tại.
23. Choose 3 digits from 1, 2, 3, 4, 6, 8 and 0 to form 3-digit numbers. How many even number(s) greater than 300 is / are there? (The repetition of digits is not allowed)
Digit: Chữ số; 3-digit number: Số có 3 chữ số; Even number: Số chẵn; Greater than: Lớn hơn; Repetition of digits is not allowed: Các chữ số không được lặp lại.
24. A flight of stairs has 10 steps. Peter can go up for 1 step, 2 steps or 3 steps each time. How many way(s) is / are there for Peter to go up the stairs?
Step: Bước; Way: Cách.
25. Numbers are drawn from 80 integers 20 to 99. At least how many number(s) is / are drawn at random to ensure that there are two numbers whose sum is 85?
Integer: Số nguyên; At least: Ít nhất; Random: Ngẫu nhiên; Ensure: Chắc chắn; Sum: Tổng.
~ End of Paper ~
1: the perimeter of a circle is 15,7 dm. Its's area is...cm2
2: the ratio of the number of girls to the number of boys in a classroom is 5:4. When 10 girls left the classroom, the ratio of the number of boys to the number of girls became 4:3. How many students were in the classroom at first?
3: 47/250 dm3=...cm3
4: At the party 60% of the boys are dancing with 80% of the girls. How many people are dancing if there are 35 people ( A pair cludes only one boy and one girl)
5: An aquarium is 8dm deep, 12 dm long and 0,3 m wide. What is the volume of the aquarium in cubic centimeter?. Answer: the volume of the aquarium is...cm3
given the digits from 0 to 5 if repetition is not allowed, how many four-digit codes that are greater than 2000 and divisible by 2 are possible? Answer:...
There are 23 kids seated in a row. They call out the numbers from left to right as 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, … for the first round. They call out 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, … from right to left for the second round. How many kids call out the same number in two rounds?
1>My class of 32 students are going to a Fun Fair for children and need to buy entrance tickets for each student. The price of an entrance ticket is 5,000 dong. The good news is that when we buy 5 tickets, the Fun Fair gives us 1 extra ticket for free. How much does my class have to pay to buy enough tickets for the whole class?
2>Minh’s family needs to tile the floor of a rectangular room, 5 m in length and 3.8 m in width, with square tiles. The length of the side of each tile is 0.5 m. Each of the tiles close to the wall, if not a whole one, is cut from a whole tile. The total number of tiles needed to tile the room is ?
3>A student cycles from home to school in a distance of 1,200 m with speed of 2.5 m/s. There are 4 crossroads on the way; the time to stop for red lights at each crossroad is 30 s the longest. The longest time it takes the student to reach school is?
Problem 8. A cuboid container has dimensions as in the figure. The container has 54 liters of water in it. Bình wants to know a full bucket contains how many liters of water, so he pours the whole bucket of water into the container and finds that the level of the water is now 7 8 the height of the container. From that, he is able to calculate how many liters of water a full bucket contains. If the container is empty, how many buckets of water must Bình pour into the container to make it full?
