Question

A student wants to buy 3 cds, but assume 5 cds feature the piano, 6 cds feature the trumpet, and 3 cds feature the saxaphone.
I figured there are 364 ways for 3 cd's to be selected.
In how many ways can the selection be made if cds featuring at least 2 different instruments are selected?_______________--

Answer 1

Moving on to computing probabilities by using equally likely outcomes after this

Answer 2

haha

Answer 3

HOLY COW

Answer 4

How does that happen

Answer 5

i can copy and paste them

Answer 6

if you cant see the first part of your solution

Answer 7

no

Answer 8

I'll try again. Patience is a good thing. :)

Answer 9

you dont have to
I am considering moving on to some other stuff that i am not sure how to do at all

Answer 10

nope

Answer 11

i tried that earlier

Answer 12

I want to do it. You can move on to another problem while I work on this.

Answer 13

Your call man i have spent A LOT of time on these 27 questions
our exam questions are coming directly from these Homework problems like this

Answer 14

I will post another shortly im sure

Answer 15

Here's where I messed up. The problem is at least 2 different instruments are selected? I calculated at least 2 of the SAME instrument.

Answer 16

yes that is correct

Answer 17

i need to sign off for a moment bu i will be back in 5-10 mins at the most

Answer 18

Okay, no rush. I just cleaned up my work area for my next take on this problem.

Answer 19

im back around

Answer 20

P = Piano, S = Sax, T = Trumpet

Of the 3 cds we are buying, 2 could be of the same instrument and 1 of another instrument.

I see the following cases:

PPT, PTT and PPS, PSS, and TTS, TSS. Do you see others before we calculate?

Answer 21

I don't

Answer 22

PPT, PTT

PPT==> C(5,2) times C(6,1) = 60

PTT ==> C(5,1) times C(6,2) = 75

Subtotal 1: 135 (Not Finished)

Answer 23

PPS, PSS

PPS ==>C (5,2) times C (3,1) = 30

PSS ==> C(5,1) times C(3,2) = 15

Subtotal 2: 45 (Not Finished)

Answer 24

TTS, TSS

TTS==> C(6,2) times C(3,1) = 45

TSS ==> C(6,1) times C(3,2) = 18

Subtotal 3: 63 (Not Finished)

Answer 25

Answer: Total of Subtotals of cases: 135 + 45 + 63 = 243 ways.

Answer 26

CW, what about this answer of 243?

Answer 27

no it didnt work

Answer 28

What did we miss? By the way, is 314 the answer? I don't think so but tried something different.

Answer 29

no

Answer 30

We missed the case where all three are different such as P T S

Answer 31

hmmm

Answer 32

PTS

C(5,1) times C(6,1) times C(3,1) = 90

Answer 33

So, the corrected answer is the

Answer: Total of Subtotals (exactly 2 different cases plus all 3 differnt: : 135 + 45 + 63 + 90 =333. Answer:333

Answer 34

Bad news, CW?

Answer 35

what?

Answer 36

The answer -- 333. Right or wrong.

Answer 37

right hahaha

Answer 38

awesome man

Answer 39

ly cow

Answer 40

holy

Answer 41

Sure it's right? There may be another case out there, and we'll find it.

Answer 42

no that is correct

Answer 43

Okay, where are the other problems?
"I will post another shortly im sure" you said.

Answer 44

yea i will in a moment

Answer 45

they are a different section