Question

WILL GIVE MEDAL IF YOU TEACH ME HOW
A charity is selling raffle tickets at $10 apiece. Ten third-place winners will be drawn, each winning $20. Five second-place winners will be drawn, each winning $50. Finally, one grand prize of $200 will be awarded. If 100 tickets are sold, what is the expected value of one ticket?

Answer 1

HI!!

Answer 2

Hello!

Answer 3

there is an easy way to do this, and a probability way
lets do it the easy way first

Answer 4

Alright. I'd also like to know how to do it the probability way. I have a whole test on these types of questions

Answer 5

ok we can do it both ways, they are actually the same, just look different

Answer 6

alright

Answer 7

first buy up all 100 tickets at $10 each
how much do you spend total?

Answer 8

$1000

Answer 9

right
and since you bought all the tickets, you win all the money
how much do you win total? (take your time on this one)

Answer 10

$650

Answer 11

looks right

Answer 12

ok so you spent $1000, got back $650 how much did you lose?

Answer 13

$350

Answer 14

(three fiddy)

Answer 15

exactly
now averaged over the (lol)

Answer 16

now averaged over the 100 tickets you bough you lost \[\frac{350}{100}=3.50\]
expected value is \(-\$3.50\)

Answer 17

ah alright. that makes a lot of sense. it just wasnt explained very well.

Answer 18

Thank you!

Answer 19

would you like to do it the probability way?

Answer 20

wait a second

Answer 21

you can see that it is the same, just looks different

Answer 22

the multiple choice answers are:

A.
–$10.00
B.
$6.50
C.
$10.00
D.
$216.67

Answer 23

i'll check my adding again

Answer 24

really??

Answer 25

no i checked it is right

Answer 26

hmmm. I'm not sure. what you said seems to make sense to me

Answer 27

i guarantee you what i said is correct

Answer 28

maybe they are not counting the amount you lose

Answer 29

thats what im thinking

Answer 30

that would be B, right?

Answer 31

if they're not counting the amount lost

Answer 32

and saying that the expected value is \(\$6.50\) which means if you spent \($10\) you lose \(\$3.50\) but that is not a true expected value

Answer 33

the expected value is the amount you win times the probability you win it, added up, but you should also include the amount you lose as a negative

Answer 34

I know. that seems weird to me

Answer 35

yours makes more sense realistically

Answer 36

because it is wrong
you would "expect" the expected value of a lottery ticket to be negative, otherwise the charity would not make any money

Answer 37

exactly

Answer 38

-3.50 to you , +3.50 per ticket to them
tell your teacher!

Answer 39

I would if i had a teacher right now. Im on the last test of my online geometry course and they didnt explain it very well at all. maybe because they have no idea what they're talking about lol

Answer 40

if this is geometry i am an old man

Answer 41

well i can hope that 6.50 is probably the right answer

Answer 42

yeah it is the only one of the bunch that makes sense, go with that one

Answer 43

I know. I was thinking the same thing

Answer 44

welcome to South Dakota state standards

Answer 45

well thanks for the help!

Answer 46

if you have the time could i get help with one more? it seems to be a little different. if not thats okay

Answer 47

sure

Answer 48

In a certain board game, a standard number cube is rolled to determine the number of spaces a player gets to move. Use the table above to determine the expected value of the number of spaces a player moves. Round the answer to the nearest tenth.

Answer 49

unless it is really geometry, because i am clueless about that

Answer 50

posting the table in just a sec

Answer 51

one "number cube" aka one die?

Answer 52

yep! lol

Answer 53

this online course was so poorly designed its not even funny

Answer 54

each outcome has probability \(\frac{1}{6}\) so really all you have do to is add and divide by 6

Answer 55

\[\huge \frac{6+3+3-3-3+1}{6}\]

Answer 56

aka \[\frac{7}{6}\] and please don't tell me that is not an answer choice !!

Answer 57

I got 1.16666.... which rounds to 1.2

Answer 58

which is an answer!

Answer 59

ok i they love decimals pick that one
who writes this gibberish?

Answer 60

No clue. A lot of the time they have trouble formulating a sentence. Sometimes major grammatical errors. It's a pain in the rear

Answer 61

FLVS or some other criminal enterprise?

Answer 62

Edgenuity, aka education2020, surprisingly

Answer 63

There were so many cases where they'd say something like an angle measuring 135º or something, and then the picture of it looking like a 45º angle

Answer 64

Obviously looking acute but they swear it measures over 90º

Answer 65

imagine
remember that these questions are written mostly by middle school math teachers or (mainly) starving graduate students living on ramen noodles and beer. they are rarely checked for accuracy

Answer 66

Probably. I've had to retake tests before simply because the right answer just wasn't in the answer choices. I had to get an actual teacher from my highschool to verify that I was right and the grading system was wrong.

Answer 67

nothing like an "actual teacher" lol

Answer 68

Sorta. She prefers "Librarian"

Answer 69

you got more or is that it?

Answer 70

LOLOLOL!!!

Answer 71

well there is another but I think I got it

Answer 72

ok good luck !

Answer 73

this is getting ridiculous

Answer 74

im just done