The value of 49C3 + 48C3 + 47C3 + 46C3 + 45C3 + 45C4 is:
Which one of the following graphs accurately represents the plot of partial pressure of CS₂ vs its mole fraction in a mixture of acetone and CS₂ at constant temperature?

The method of forming subsets by selecting data from a larger set in a way that the selection order does not matter is called the combination.
But you are only allowed to pick three.
It is used for a group of data (where the order of data doesn’t matter).