Combinations ${}^n C_r$ (nCr = n!/(r!(n−r)!): unordered r-subset from n distinct)
jee-mainjee-advanced
nCr = n!/(r!(n−r)!) — unordered r-subset from n distinct
What each symbol means
| Symbol | What it stands for |
|---|---|
| n,r | 0≤r≤n integers |
When to use this
Distinct objects; selection without order.