Thread: Data Management Problem Help

I know I may be asking too much on this one, but please hear me out. I'm taking a data management course in summer school, summer school is only 3 weeks long. So basically, I'm learn a large amount of material everyday for six hours, material that would normally take a semester(5 months) to cover. So, as you may imagine, the pacing of the course is very quick.

So please sympathize with situation. I really need help with this problem.

Problem:

This is an organized counting problem.

a) In how many ways could you choose two fives, one after the other, from a deck of cards?

b) In how many ways could you choose a red five and a spade, one after the other?

c) In how many ways could you choose a red five or a spade?

d) In how many ways could you choose a red five or a heart?

Answers:
a)12
b)26
c)15
d)14

Originally Posted by Morphayne

I know I may be asking too much on this one, but please hear me out. I'm taking a data management course in summer school, summer school is only 3 weeks long. So basically, I'm learn a large amount of material everyday for six hours, material that would normally take a semester(5 months) to cover. So, as you may imagine, the pacing of the course is very quick.

So please sympathize with situation. I really need help with this problem.

Problem:

This is an organized counting problem.

a) In how many ways could you choose two fives, one after the other, from a deck of cards?

b) In how many ways could you choose a red five and a spade, one after the other?

c) In how many ways could you choose a red five or a spade?

d) In how many ways could you choose a red five or a heart?

Answers:
a)12
b)26
c)15
d)14

Ask your self are you picking with replacement and does order matter?
1) No and Yes (although the wording "one after another" took me a second - I think they mean that it matters).

Ok so you use combinations:

You want to pick 2 cards from 4. Even though there are 52 cards, it doesn't matter for this. You want to know how many ways to pick from the set of 5's.



2) No and Yes

You want to pick 1 from 2 cards (2 red 5's) and then pick 1 from 13 cards (13 spades)

2*13 = 26

Technically you could do

but you get the same thing. It's just the more general approach.

3) Hint: This question is really asking (since you are only picking 1 card) how many cards satisfy (either red 5 or spade)?

4) Hint: This question is really asking (since you are only picking 1 card) how many cards satisfy (either red 5 or heart)? (notice that these sets overlap).