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What is 20C4?

This is a binomial coefficient question. 20C4 is notation for a combination without repetition, so you are choosing 4 items from 20 distinct items and order does not matter.

Exact result

4,845

The binomial coefficient C(20, 4) is 4,845.

20C4 counts unordered groups of 4 drawn from 20 distinct items. It is the same value as 20 choose 4.

Worked steps

Show your work

  1. Inputs: n = 20, r = 4
  2. Formula: C(n, r) = nCr = n! / r!(n - r)!
  3. Substitute: C(20, 4) = 20! / (4!(20-4)!)
  4. Steps: 2,432,902,008,176,640,000 / (24 x 20,922,789,888,000)
  5. Result: The binomial coefficient C(20, 4) is 4,845.

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20C4 counts unordered groups of 4 drawn from 20 distinct items. It is the same value as 20 choose 4.

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