How Many Permutations for Pressing 4 Out of 8 Switches?

In summary, the speaker is asking for help with calculating the number of permutations that can be made by pressing any 4 out of 8 switches. They mention that they believe the answer is 40 combinations, but they are not confident in their math skills. Robert suggests using the formula 8!/(4!4!)=70 and the speaker thanks him.
  • #1
novolts
2
0
Good evening to all
I wonder if anyone can help please I have 8 switches b1,b2,b3,b4,b5,b6,b7,b8 I am trying to work out how many permutations I would have if I pressed any 4 of the 8 switches ie if I pressed b1,b3,b,7,b8 to make a circuit or it could be b3,b5,b6,b7 doing it by long hand I reckon it is 40 combination.
I fully understand if no one wishes to answer the question but I am completely useless at maths
Thank you to all
 
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  • #2
8!/(4!4!)=70
 
  • #3
Thankyou Robert will have to get paper and pencil out again
 

FAQ: How Many Permutations for Pressing 4 Out of 8 Switches?

What is "Any 4 from 8 switch permutation"?

"Any 4 from 8 switch permutation" is a mathematical concept that refers to the number of ways 4 items can be chosen from a set of 8 items, where the order of the items does not matter.

How many possible permutations are there for "Any 4 from 8 switch permutation"?

There are 70 possible permutations for "Any 4 from 8 switch permutation". This can be calculated using the formula nCr = n!/(r!(n-r)!), where n is the total number of items (in this case, 8) and r is the number of items chosen (in this case, 4).

What are some real-life applications of "Any 4 from 8 switch permutation"?

"Any 4 from 8 switch permutation" is often used in statistics and probability, as well as in computer science and cryptography. It can also be applied in games, such as selecting a team from a pool of players or creating unique combinations in a puzzle or code-breaking game.

How does "Any 4 from 8 switch permutation" differ from other types of permutations?

In "Any 4 from 8 switch permutation", the order of the chosen items does not matter. This means that selecting items A, B, C, and D is considered the same as selecting items D, C, B, and A. Other types of permutations, such as "4 from 8 with replacement", allow for the same item to be chosen more than once and consider the order of the items in the selection.

What are some strategies for solving problems involving "Any 4 from 8 switch permutation"?

One strategy is to use the formula nCr = n!/(r!(n-r)!), as mentioned above. Another strategy is to list out all the possible combinations by hand, which can be helpful for smaller sets of items. Additionally, using a computer program or calculator can quickly generate all the possible permutations for larger sets.

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