Hi All,

I am generally not sure when to add vs when to multiply. Why did we multiply the 2 combinations together in this case? And what would be the case to add them?

Thanks!

Hi All,

I am generally not sure when to add vs when to multiply. Why did we multiply the 2 combinations together in this case? And what would be the case to add them?

Thanks!

What I keep in mind while doing combination questions is that,

AND = Multiply

OR = Add

If one task can be done in ‘m’ ways and another in ‘n’ ways then, first AND second can be done in m*n ways.

If one task can be done in ‘m’ ways and another task can be done in ‘n’ ways then, first OR second ( but not both ) task can be done in ‘m+n’ ways.

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