Formulas To Solve Combination

August 30, 2019

Formulas for Combination & Definitions

Combination: Each of the different groups or selections which can be formed by taking some or all of a number of objects is called a combination. This is denoted by ⁿC_r.

Combination is selection of all part or part of a set or objects.
To calculate a combination, you will need to calculate a factorial.
Read Also – Tips & tricks to solve combination questions

Combination Formulas

•Number of all combinations of n things, taken r at a time, is given by
ⁿC_r = n!/(r!) (n-r)!
•n-combinations from a set with n elements (without repetition)
ⁿC_r = n!/(r!) (n-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

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