I'm really sorry for posting all these questions but i really need help.(adsbygoogle = window.adsbygoogle || []).push({});

1. Show that

C 2(2n-1, n-1) = C (2n, n)

Heres what i did.

2 x (2n-1)!/2n-1-n-1)!(n-1)! = 2n!/n

I dont know how to get the LS to equal the RS.

2. Determine the probability of each of the following.

a) a five card poker hand dealt from a standard deck of 52 playing cards results a full house (3 of a kind and 2 of a kind)

b)Two face cards are drawn in a row (w/o replacement) from a standard deck of 52 playing cards given that the first card is a king.

c) a committee of 6 people randomly chosen from seven males and eight females is either all male or female

d) in a six person sprint, Jessie finishes first, Marnie second and Raul last.

Heres what i did.

a)52!/3! x 2! but i think thats wrong. then i did 5 over that total but they have 6 as a numerator and i cant get that.

b)this one i dont kno how to do.

c) C(7,0) + C (8,0)

Is that right?

3. Use the appropriate counting techniques

a)In how many permutations of the digits 123456789 are the number 1 and 2 beside each other.

b)A school has 480 girls and 520 boys. How many committees of 5 members can be formed if there must be atleast 1 boy on each committe.

c) How many groups consisting of at least 2 people can be chosen from a group of 10 people.

a) P(9,2) again its not right and i dont know what to do

b) C (480,4) x C (520, 1) + C (480, 3) x C (520, 2) + C (480,2) x C (520, 3) + C (480, 1) x C (520, 4) + C (480,0) x (520, 5)

I think im totally off on this one.

c) 10!/(10-2)!

Is this right?

Again sorry for all these questions but i really need to understand this.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Lots more questions

**Physics Forums | Science Articles, Homework Help, Discussion**