Reason + numbers - practice problems - page 19 of 43
Number of problems found: 851
- Birthdays 9011
Three sisters have birthdays today, and their ages are in the ratio of 2:3:4. In two years, their ages will be in the ratio of 5:7:9. Find what their ages will be in four years. - Graduation party
There were 15 boys and 12 girls at the graduation party. Determine how many four couples can be selected. - Notebooks 8651
I need to buy exercise books and covers. One notebook costs CZK 12, and one cover costs CZK 3. I have one fifty crown and one twenty crown. How many notebooks and covers can I buy for it? Come up with more options. - Determine 8611
Determine all natural numbers A and B pairs for which the sum of twice the least common multiple and three times the greatest common divisor of natural numbers A and B is equal to their product.
- Solutions 8481
For which integers x is the ratio (x + 11) / (x + 7) an integer? Find all solutions. - Justification 8468
The natural number n has at least 73 two-digit divisors. Prove that one of them is the number 60. Also, give an example of the number n, which has exactly 73 double-digit divisors, including a proper justification. - Two math problems
1) The sum of twice a number and -6 is nine more than the opposite of that number. Find the number. 2) A collection of 27 coins, all nickels, and dimes worth $2.10. How many of each coin are there? The dime, in United States usage, is a ten-cent coin. A n - Pine's forest
There were so many pines in the forest that they were sequentially numbered 1, 2, 3,..., and would use three times more digits than the pine trees alone. How many pine trees were there in the forest? - Balls 8358
We have five red, four blue, and seven white balls in the bag. At least how many balls do we have to pull out to have at least one white ball on the table?
- Five-digit 8357
How many five-digit numbers can you create from the numbers 1,2,3,4,5,6 if 1 and 2 must always be next to each other? We cannot repeat the digits. - Generated 8349
The numbers 1,2,3,4,5 are given. Role: a) how many 4-digit numbers can we create if the digits cannot be repeated? b) how many generated numbers will not contain the digit 1? c) How many of the generated numbers will be divisible by 5? d) How many of the - Representative 8328
How many ways can a commander and a representative of a 20-member group be elected? - Determine 8322
Determine which number belongs instead of the question mark 25 -? - 205 - 610 -1825 - Probability 8280
We have ten white, ten red, and ten blue balls in our pockets. We selected five white, two red, and three blue balls. What is the probability that we will pick a white ball in the next move?
- Observed 8276
We observed road traffic. We only saw bikes and cars. There were a total of 40 laps on the road. List at least three options how many bikes could be and how many cars? - Bookshelf and books
How many ways can we place seven books on a bookshelf? - 4-digit 8231
How many 4-digit numeric pin codes can be created so that not all four digits are identical? - 102—likewise 8205
The number 20 137 is "like" the number 73 102—likewise, the decimal numbers 41.9 and 9.14, or 31.08 and 80.13, like each other. Find two mutually exclusive numbers whose product is 357.435. - Iron pole
The iron pole is in the ground 2/5 of its length, partly above the ground 1/3 is yellow, and the unpainted section is 6 m long. How long is the entire column?
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