Question

Probability question.

Answer 1

\(\large \color{black}{\begin{align}& \normalsize \text{A box contains 10 red marbles, 20 blue marbles and 30 green marbles}\hspace{.33em}\\~\\
& \normalsize \text{5 marbles are drawn from the box}\hspace{.33em}\\~\\
& \normalsize \text{what is the probability that } \hspace{.33em}\\~\\
& \normalsize \text{(i) atleast one will be green?}\hspace{.33em}\\~\\
\end{align}}\)

Answer 2

may be work the probability for "none will be green"
then subtract that from 1

Answer 3

phi is a person , he is not a method

Answer 4

but substracting from (1- "none will be green")

Will resemble all will be green

Answer 5

whats the negation of "none of them are green" ?

Answer 6

do you say "none of them are green" to below set ?

{B R B R G B}

?

Answer 7

All will be green ?

Or

At least one will be green .

i am confused

Answer 8

\(\color{blue}{\text{Originally Posted by}}\) @ganeshie8
do you say "none of them are green" to below set ?

{B R B R G B}

?
\(\color{blue}{\text{End of Quote}}\)

one G is green.

Answer 9

negation of "none of them are green"

is

"at least one of them is green"

Answer 10

ok my english / logic is weak.

Answer 11

your english/logic is fine, it takes some to see why above is true
lets do some examples may be

Answer 12

ok

Answer 13

whats the opposite of statement : "all of them are green"

Answer 14

whats the opposite of statement : "all of them did good"

Answer 15

none of them is green

Answer 16

wrong

Answer 17

y

Answer 18

opposite of

"all of them are green"

is

"not all of them are green"

which is same as

"at least one of them is not green"

Answer 19

ohk

Answer 20

lets do couple more quick examples

Answer 21

whats the opposite of "at least one of my shirts is red"

Answer 22

None of my shirts is red

Answer 23

good,

whats the opposite of "all of my shirts are blue"

Answer 24

all of my shirts are not blue

Answer 25

do you mean : "there is at least one shirt that is not blue" ?

Answer 26

ya this one

Answer 27

good
are you confident or want to do couple more ?

Answer 28

confident

Answer 29

so from probability rules you must be knowing that
\[P(A) + P(A)' = 1\]

Answer 30

yes

Answer 31

In our case,

\(P(A)\) : at least one of them is green
\(P(A)'\) : ?

Answer 32

none of them is green

Answer 33

good, find its probability

Answer 34

=1-(30C5)/(60C5)

Answer 35

Perfect!

Answer 36

that is correct, but could you explain how you got that ?

Answer 37

p'(a)=1-p(a)

p(a)=none of them is green

Answer 38

looks good!

Answer 39

do you double check ur answer by working it using an alternative method ?

Answer 40

as per probablity the chance of getting 1 from dice is 1/6

so is it true that if i threw a dice 6 times there will be 1 at least

Answer 41

no i check by back of the book

Answer 42

probability is never "exactly" true

Answer 43

we say that seeing "1" at least once is more likely when you threw a dice 6 times

Answer 44

sometimes you might not get a single 1 even if you throw it 100 times

that can happen

Answer 45

ok so its not true

Answer 46

yes, you can't use probability to win bets

Answer 47

yep