LenaA wrote:

I did not get your example with meals.

But I will give you mine...also food related...

You are going to have a dessert and you have a selction of 4 chocolate cakes and 3 cheese cakes. You are going to eat 2 types of cake...how many desserts options can you have?

1) you are going to have one chocolate and one cheese cake then you have \(4\times 3=12\) dessert options

2) there is no limitation you can have 2 chocolate or 2 cheese or one chocolate and one cheese...

then you have 7 types of cake and you can have \(7C2=\frac{7!}{5!2!}\)dessert options...

ok now it's clear, but how can I calculate the following in the exam? \(7C2=\frac{7!}{5!2!}\)

thanks,