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Stanry
Nombre de usuario
Stanry
Puntuación
400
Membership
Stats
Preguntas
123
Respuestas
12
123 Questions
12 Answers
0
20
0
+400
Counting
The following cards are split into four piles at random, so that every pile contains the same number of cards. What is the probability that every pile contains an Ace?
The cards are:
Ace of clubs
Ace of diamonds
lee mas ..
Stanry
17 abr 2025
0
12
0
+400
Counting
How many positive integers are there whose digits strictly decrease from left to right, and have at most one even digit, and the sum of the digits is 6?
Stanry
16 abr 2025
0
6
1
+400
Counting
How many positive integers are there whose digits strictly decrease from left to right, and the sum of the digits is 6?
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Stanry
16 abr 2025
0
11
1
+400
Counting
How many 7-digit sequences have a digit that appears at least 6 times?
(For example, 3339333 and 0200000 are two such sequences. A sequence is allowed to begin with 0.)
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Stanry
15 abr 2025
0
14
0
+400
Counting
Find the number of ways of arranging one A, two Bs, three Cs, and four Ds, so that no two Bs are next to each other, no two Cs are next to each other, and no two Ds are next to each other.
Stanry
15 abr 2025
0
16
0
+400
Counting
We choose a positive divisor of 20^{20} at random (with all divisors equally likely to be chosen). What is the probability that we chose a multiple of 5?
Stanry
14 abr 2025
0
24
0
+400
Counting
How many subsets of \{0, 1, \dots, 9\} have the property that there are at least two elements and the sum of the two largest elements is 4?
Stanry
14 abr 2025
0
16
0
+400
Counting
A permutation of the numbers (1,2,3,\dots,n) is a rearrangement of the numbers in which each number appears exactly once. For example, (2,5,1,4,3) is a permutation of (1,2,3,4,5).
Find the number of permutations (x_1, x_2, \dots, x_8)
lee mas ..
Stanry
13 abr 2025
0
14
0
+400
Counting
Find the number of sequences (a_1, a_2, a_3, \dots, a_8) such that:
* a_i \in \{1, 2, 3, 4, 5, 6, 7, 8\} for all 1 \le i \le 8.
* Every number1, 2, 3, 4, 5, 6, 7, 8 appears at least once in the sequence.
Stanry
13 abr 2025
0
21
0
+400
Counting
A standard deck of 52 cards has 13 ranks (Ace, 2, 3, 4, 5, 6, 7, 8, 9, 10, Jack, Queen, King) and 4 suits (spades, hearts, diamonds, and clubs), such that there is exactly one card for any given rank and suit.
You are dealt a hand of
lee mas ..
Stanry
13 abr 2025
0
13
1
+400
Counting
In the array below, in how many different ways can we start with the letter and move from letter to letter (horizontally, vertically, or diagonally), to spell the word "ARCS"?
A
lee mas ..
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Stanry
13 abr 2025
0
20
0
+400
Counting
How many squares in the plane have at least two points in the lattice below as vertices?
Stanry
13 abr 2025
0
3
4
2
+400
Counting
At a meeting, two scientists, two mathematicians, two historians, and two artists are to be seated around a circular table. In how many ways can they be seated so that all four pairs of people from the same discipline are seated together?
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Stanry
12 abr 2025
«
último
11
10
..
2
1
»
#1
+400
0
The number of ways is 10*9 = 90.
Stanry
1 oct 2024
«
último
0
-1
2
último
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