A bag contains 2 red, 3 green and 5 blue balls
A ball is drawn, observed and put again in the bag. Find the probability of getting all colours different.
My teacher's solution:
2/10 × 3/10 × 5/10 × 3! × 2
I don't get why that last 2 was necessary
Edit: balls are drawn 3 times
probability
asked Dec 28 '18 at 13:59
S. SuryaS. Surya
143
add a comment |
A ball is drawn, observed and put again in the bag. Find the probability of getting all colours different.
My teacher's solution:
2/10 × 3/10 × 5/10 × 3! × 2
I don't get why that last 2 was necessary
Edit: balls are drawn 3 times
probability
asked Dec 28 '18 at 13:59
S. SuryaS. Surya
143
1
So how many times do you take a ball out from the bag (and put it back)?
– Matti P.
Dec 28 '18 at 14:02
I guess you draw $3$ balls after each other. Is that correct? Further (just like you) I think that multiplying by $2$ is not correct.
– drhab
Dec 28 '18 at 14:02
Yes 3 balls sorry I forgot to mention that
– S. Surya
Dec 28 '18 at 14:06
I expect the teacher meant to write $3times 2$ instead of $3!times 2$.
– lulu
Dec 28 '18 at 14:23
add a comment |
A ball is drawn, observed and put again in the bag. Find the probability of getting all colours different.
My teacher's solution:
2/10 × 3/10 × 5/10 × 3! × 2
I don't get why that last 2 was necessary
Edit: balls are drawn 3 times
probability
asked Dec 28 '18 at 13:59
S. SuryaS. Surya
143
A ball is drawn, observed and put again in the bag. Find the probability of getting all colours different.
My teacher's solution:
2/10 × 3/10 × 5/10 × 3! × 2
I don't get why that last 2 was necessary
Edit: balls are drawn 3 times
probability
probability
asked Dec 28 '18 at 13:59
S. SuryaS. Surya
143
asked Dec 28 '18 at 13:59
S. SuryaS. Surya
143
edited Dec 28 '18 at 14:07
S. Surya
asked Dec 28 '18 at 13:59
S. SuryaS. Surya
143
asked Dec 28 '18 at 13:59
S. SuryaS. Surya
143
asked Dec 28 '18 at 13:59
S. SuryaS. Surya
143
143
1
So how many times do you take a ball out from the bag (and put it back)?
– Matti P.
Dec 28 '18 at 14:02
I guess you draw $3$ balls after each other. Is that correct? Further (just like you) I think that multiplying by $2$ is not correct.
– drhab
Dec 28 '18 at 14:02
Yes 3 balls sorry I forgot to mention that
– S. Surya
Dec 28 '18 at 14:06
I expect the teacher meant to write $3times 2$ instead of $3!times 2$.
– lulu
Dec 28 '18 at 14:23
add a comment |
1
So how many times do you take a ball out from the bag (and put it back)?
– Matti P.
Dec 28 '18 at 14:02
I guess you draw $3$ balls after each other. Is that correct? Further (just like you) I think that multiplying by $2$ is not correct.
– drhab
Dec 28 '18 at 14:02
Yes 3 balls sorry I forgot to mention that
– S. Surya
Dec 28 '18 at 14:06
I expect the teacher meant to write $3times 2$ instead of $3!times 2$.
– lulu
Dec 28 '18 at 14:23
1
1
So how many times do you take a ball out from the bag (and put it back)?
– Matti P.
Dec 28 '18 at 14:02
So how many times do you take a ball out from the bag (and put it back)?
– Matti P.
Dec 28 '18 at 14:02
I guess you draw $3$ balls after each other. Is that correct? Further (just like you) I think that multiplying by $2$ is not correct.
– drhab
Dec 28 '18 at 14:02
I guess you draw $3$ balls after each other. Is that correct? Further (just like you) I think that multiplying by $2$ is not correct.
– drhab
Dec 28 '18 at 14:02
Yes 3 balls sorry I forgot to mention that
– S. Surya
Dec 28 '18 at 14:06
Yes 3 balls sorry I forgot to mention that
– S. Surya
Dec 28 '18 at 14:06
I expect the teacher meant to write $3times 2$ instead of $3!times 2$.
– lulu
Dec 28 '18 at 14:23
I expect the teacher meant to write $3times 2$ instead of $3!times 2$.
– lulu
Dec 28 '18 at 14:23
add a comment |
2 Answers
2
active
oldest
votes
The last $2$ should not be there. The first three terms give the chance of getting specifically red,green,blue. The $3!$ is the number of orders of colors and you are done.
answered Dec 28 '18 at 14:13
Ross MillikanRoss Millikan
292k23197371
add a comment |
Yes, you have to delete the last 2.
Maybe the teacher wanted to just put $3 cdot 2$ and not $3! cdot 2$
answered Dec 28 '18 at 14:35
Angel MorenoAngel Moreno
37915
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3054913%2fa-bag-contains-2-red-3-green-and-5-blue-balls%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
The last $2$ should not be there. The first three terms give the chance of getting specifically red,green,blue. The $3!$ is the number of orders of colors and you are done.
answered Dec 28 '18 at 14:13
Ross MillikanRoss Millikan
292k23197371
add a comment |
The last $2$ should not be there. The first three terms give the chance of getting specifically red,green,blue. The $3!$ is the number of orders of colors and you are done.
answered Dec 28 '18 at 14:13
Ross MillikanRoss Millikan
292k23197371
add a comment |
The last $2$ should not be there. The first three terms give the chance of getting specifically red,green,blue. The $3!$ is the number of orders of colors and you are done.
answered Dec 28 '18 at 14:13
Ross MillikanRoss Millikan
292k23197371
The last $2$ should not be there. The first three terms give the chance of getting specifically red,green,blue. The $3!$ is the number of orders of colors and you are done.
answered Dec 28 '18 at 14:13
Ross MillikanRoss Millikan
292k23197371
answered Dec 28 '18 at 14:13
Ross MillikanRoss Millikan
292k23197371
answered Dec 28 '18 at 14:13
Ross MillikanRoss Millikan
292k23197371
answered Dec 28 '18 at 14:13
Ross MillikanRoss Millikan
292k23197371
292k23197371
add a comment |
add a comment |
Yes, you have to delete the last 2.
Maybe the teacher wanted to just put $3 cdot 2$ and not $3! cdot 2$
answered Dec 28 '18 at 14:35
Angel MorenoAngel Moreno
37915
add a comment |
Yes, you have to delete the last 2.
Maybe the teacher wanted to just put $3 cdot 2$ and not $3! cdot 2$
answered Dec 28 '18 at 14:35
Angel MorenoAngel Moreno
37915
add a comment |
Yes, you have to delete the last 2.
Maybe the teacher wanted to just put $3 cdot 2$ and not $3! cdot 2$
answered Dec 28 '18 at 14:35
Angel MorenoAngel Moreno
37915
Yes, you have to delete the last 2.
Maybe the teacher wanted to just put $3 cdot 2$ and not $3! cdot 2$
answered Dec 28 '18 at 14:35
Angel MorenoAngel Moreno
37915
answered Dec 28 '18 at 14:35
Angel MorenoAngel Moreno
37915
answered Dec 28 '18 at 14:35
Angel MorenoAngel Moreno
37915
answered Dec 28 '18 at 14:35
Angel MorenoAngel Moreno
37915
37915
add a comment |
add a comment |
Thanks for contributing an answer to Mathematics Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3054913%2fa-bag-contains-2-red-3-green-and-5-blue-balls%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
So how many times do you take a ball out from the bag (and put it back)?
– Matti P.
Dec 28 '18 at 14:02
I guess you draw $3$ balls after each other. Is that correct? Further (just like you) I think that multiplying by $2$ is not correct.
– drhab
Dec 28 '18 at 14:02
Yes 3 balls sorry I forgot to mention that
– S. Surya
Dec 28 '18 at 14:06
I expect the teacher meant to write $3times 2$ instead of $3!times 2$.
– lulu
Dec 28 '18 at 14:23