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How many combinations are there if there are seven numbers and you have to have a four number combination?
But if you are not allowed to repeat, that means that every time you pick a digit for one spot, there will be one less digit for the next, and one less for the next, and so on. So, the first number can have seven possibilities, the second can have six, the third can have five, and the last can have four possible digits. That means there are 7 x 6 x 5 x 4 = 840 possible combinations for your lock, only about a third as many.
Check out the related link at MathsIsFun. It has very good information on this subject.
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That is true for PERMUTATIONS, but not for combinations. In a combination, the order of digits does not matter so that 1234 is the same as 1342 or 4213 ext.
As a result you have 7C4 = 7!/[4!*(7-4)!] = 7*6*5/(3*2*1) = 35 combinations - not 2401.
Incidentally, nCr is the notation for the number of combinations of r objects taken from n objects - exactly what the question asked for.
What else can I help you with?
How many combinations are there in a seven digit phone number?
There is only one combination. There are many permutations, though.
How many combinations of 6 numbers if you have 7 numbers?
Well, honey, if you have 7 numbers and you're picking 6 of them, there are 7 ways to pick the first number, 6 ways to pick the second number, 5 ways for the third number, and so on until you've picked all 6 numbers. So, the number of combinations would be 7 x 6 x 5 x 4 x 3 x 2, which is 5040. It's like picking out outfits for the week, just with numbers instead of clothes.
How many seven digit numbers contain the number seven at least once?
To find the total number of seven-digit numbers that contain the number seven at least once, we can use the principle of complementary counting. There are a total of 9,999,999 seven-digit numbers in total. To find the number of seven-digit numbers that do not contain the number seven, we can count the number of choices for each digit (excluding seven), which is 9 choices for each digit. Therefore, there are 9^7 seven-digit numbers that do not contain the number seven. Subtracting this from the total number of seven-digit numbers gives us the number of seven-digit numbers that contain the number seven at least once.
What numbers are not divisible by 7?
There is an infinite number of numbers that are not divisible by seven!
What is two and seven eighths as a whole number?
Mixed numbers can't be whole numbers.
How many combinations are there if there are seven numbers and you have to have a six number combination?
There are: 7C6 = 7
How many combinations can you get with 8 numbers in a seven number combination?
To calculate the number of combinations possible with 8 numbers in a seven-number combination, you would use the combination formula, which is nCr = n! / (r!(n-r)!). In this case, n = 8 and r = 7. Plugging these values into the formula, you get 8C7 = 8! / (7!(8-7)!) = 8. Therefore, there are 8 possible combinations with 8 numbers in a seven-number combination.
What are the combinations of 1 through 10 with out using them twice?
There is 1 combination of all ten numbers, 10 combinations of one number and of nine numbers, 45 combinations of two or eight numbers, 120 combinations of three or seven numbers, 210 combinations of four or six numbers and 252 combinations of five numbers. That is 1023 = 210 - 1 in total.
How many combinations of six numbers can be had from seven numbers?
The number of combinations of six numbers that can be made from seven numbers will depend on if you can repeat numbers. In all there are over 2,000 different numbers that can be made.
What is an easy way to generate numbers with an odd number of factors?
Start with the factors. Multiply combinations of three prime factors, then combinations of five, then seven, etc. All generated numbers will be guaranteed to have an odd number of prime factors.
How many combinations are there in a seven digit phone number?
There is only one combination. There are many permutations, though.
How many combinations of 6 numbers are there in seven numbers 7 numbers?
Revise your question, it makes no sence.
Why is number seven the most common number to roll on a pair of dice?
Because every combination is equally probable, but more combinations sum to seven than to any other total. There are 36 possible combinations; of these seven will produce 7, only one will give 2 and only one will give 12.
How many combinations of 6 numbers if you have 7 numbers?
Well, honey, if you have 7 numbers and you're picking 6 of them, there are 7 ways to pick the first number, 6 ways to pick the second number, 5 ways for the third number, and so on until you've picked all 6 numbers. So, the number of combinations would be 7 x 6 x 5 x 4 x 3 x 2, which is 5040. It's like picking out outfits for the week, just with numbers instead of clothes.
How many combinations of six numbers can be made from numbers 1-7?
8
Is seven a prime number?
Yes seven is a prime number and the only numbers that will go in to seven is one and seven.
How many seven digit numbers contain the number seven at least once?
To find the total number of seven-digit numbers that contain the number seven at least once, we can use the principle of complementary counting. There are a total of 9,999,999 seven-digit numbers in total. To find the number of seven-digit numbers that do not contain the number seven, we can count the number of choices for each digit (excluding seven), which is 9 choices for each digit. Therefore, there are 9^7 seven-digit numbers that do not contain the number seven. Subtracting this from the total number of seven-digit numbers gives us the number of seven-digit numbers that contain the number seven at least once.
