Formulas For Combination

Combination Formulas

• Number of all combinations of n things, taken r at a time, is given by

ⁿC_r = \frac{n!}{(n-r)! r! } n!/(r!) (n-r)!

• n-combinations from a set with n elements (without repetition)

ⁿC_r = \frac{n!}{(n-r)! r! }

• n-combinations from a set with n elements (with repetition)

^{r + n – 1}C_r = C (n, r)

Points to remember in Combination Formulas

• ⁿC_n = 1
• ⁿC0 = 1
• ⁿCr= ⁿC_{(n – r)}
• ⁿC0 + ⁿC1+ ⁿC2+ ⁿC3+ ……………+ ⁿCn = 2ⁿ

Read Also – Tips and tricks of Combination