Question

I need help plz..... ☺

Answer 1

It's 42, here's a quick trick to do this, so we know there's 7 movies, and to find the combination we know we can't choose 2 of the same movie, so to make this part easier , in your head take one movie from the stack out of the stack now there's 6 movies. It's now just the "plug and play" step , (7)*(6)=(42)
I'm sorry If this is to long of an explanation, but I hope that this helps you understand on how to do this problem. Have a nice day :)

Answer 2

Use factorials to solve this question.

When you are choosing multiple items out of a set, the permutation formula will be represented by the following:


`(n!)/((n-r)!)`

n represents the total amount of items, and r represents the number of items you're choosing from the set.

The stack has 7 items, and you are choosing sets of 2 items from the stack. Plug the values into the formula:


`\text{n = 7, r = 2}`

`(7!)/((7-2)!) = (7!)/(5!) = \boxed{42}`

There will be 42 different combinations to choose from.