Math Help!! Permutations and Combinations??

Question

I understand that in Permutations order does matter and in combination order doesn't matter. That is the part i dont comprehend. I feel i look into too much. Most of the time if u take something away it will some way shape or form have an effect on the outcome unless you replace it?? Just explain anything please

Answer 1

Think of it like this. If you have a pair of dice, how many ways can you roll a 7? Does it really matter which die is thrown first? This is like combinations. If you then want to figure out the chance of rolling a 7 then you need to find out all the permutations of the rolls of all the dice and all the permutations of the rolls of 7.

So in my example there are 1,6 2,5 3,4 or 3 different combinations to roll a 7. But there are 6 different permutations to roll the seven 1,6 6,1 2,5 5,2 3,4 4,3.

I hope this helps.

Answer 2

With permutations, order does matter. So x1, x2, x3 is different from x2, x1, x3; x3, x1, x2; x2, x3, x1, etc.

With combinations order doesn't matter. So x1, x2, x3 is the same as x2, x1, x3 ... etc.

So if you're picking three people for a committee out of a pool of 7 people, does the order in which they are picked matter? (i.e. who gets picked first, second, third) If it does, you would have to use the permutation formula to find out the number of possible ways to pick the three people. If not (i.e. only the people picked matter, we don't care about the order in which they were picked), then you have to use the combination formula.

Answer 3

Yes, think about blackjack with 52 cards. If someone gets a jack, you have less of a chance of getting one.

Answer 4

i don't get what you are asking, but i'm learning this stuff now too in math... hoorah!