Firstly, solve 38C15.
Then solve 42C12.
Compare your answers.
The goal here is to see if 38C15 = 42C12.
Here is the formula:
nCr = n!/(r!(n - r)!
Go for it.
You know how a puppy is a kind of dog, but not all dogs are puppies? Well, the same thing is true for lots of other categories of things, including squares and rectangles.