Probability of sum 15 when roll 3rd dice, and first roll of 2 dice at least 10
enter image description hereTwo dice have been thown, giving a total of at least 10.
What is the probability that the throw of a third die
will bring the total of the three numbers shown to 15 or higher?
I work out is 2/27. but physicsandmathstutor.com give a solution is 4/9.
i wander if you can help and explain in details. thanks
probability dice
add a comment |
enter image description hereTwo dice have been thown, giving a total of at least 10.
What is the probability that the throw of a third die
will bring the total of the three numbers shown to 15 or higher?
I work out is 2/27. but physicsandmathstutor.com give a solution is 4/9.
i wander if you can help and explain in details. thanks
probability dice
1
For example, how did you get $frac 2{27}$? Could you sketch your method?
– lulu
Nov 19 '18 at 0:12
The answer must be at least $frac26$ since the third die being $5$ or $6$ would be sufficient in every case
– Henry
Nov 19 '18 at 0:13
add a comment |
enter image description hereTwo dice have been thown, giving a total of at least 10.
What is the probability that the throw of a third die
will bring the total of the three numbers shown to 15 or higher?
I work out is 2/27. but physicsandmathstutor.com give a solution is 4/9.
i wander if you can help and explain in details. thanks
probability dice
enter image description hereTwo dice have been thown, giving a total of at least 10.
What is the probability that the throw of a third die
will bring the total of the three numbers shown to 15 or higher?
I work out is 2/27. but physicsandmathstutor.com give a solution is 4/9.
i wander if you can help and explain in details. thanks
probability dice
probability dice
edited Nov 19 '18 at 20:20
asked Nov 19 '18 at 0:04
Jan Jin
11
11
1
For example, how did you get $frac 2{27}$? Could you sketch your method?
– lulu
Nov 19 '18 at 0:12
The answer must be at least $frac26$ since the third die being $5$ or $6$ would be sufficient in every case
– Henry
Nov 19 '18 at 0:13
add a comment |
1
For example, how did you get $frac 2{27}$? Could you sketch your method?
– lulu
Nov 19 '18 at 0:12
The answer must be at least $frac26$ since the third die being $5$ or $6$ would be sufficient in every case
– Henry
Nov 19 '18 at 0:13
1
1
For example, how did you get $frac 2{27}$? Could you sketch your method?
– lulu
Nov 19 '18 at 0:12
For example, how did you get $frac 2{27}$? Could you sketch your method?
– lulu
Nov 19 '18 at 0:12
The answer must be at least $frac26$ since the third die being $5$ or $6$ would be sufficient in every case
– Henry
Nov 19 '18 at 0:13
The answer must be at least $frac26$ since the third die being $5$ or $6$ would be sufficient in every case
– Henry
Nov 19 '18 at 0:13
add a comment |
3 Answers
3
active
oldest
votes
Hint: I suggest a Probability Tree with total values then if it is 15 or more as the second branch. Calculate the probabilities individually. This should help clear any doubt you have with your answer.
add a comment |
if you list all possible events is 16, over sample space 216 events. 16/216 = 2/27
D1 D2 D3
1 4 -> 6 => 5
2 4 -> 6 => 6
3 5 -> 5 => 5
4 5 -> 5 => 6
5 6 -> 4 => 5
6 6 -> 4 => 6
7 5 -> 6 => 4
8 5 -> 6 => 5
9 5 -> 6 => 6
10 6 -> 5 => 4
11 6 -> 5 => 5
12 6 -> 5 => 6
13 6 -> 6 => 3
14 6 -> 6 => 4
15 6 -> 6 => 5
16 6 -> 6 => 6
for people think use conditional probability, I think the wrong part is use probabilty 1/6 for two dice sum 10, applies to each event.
add a comment |
Let $A$ be the event "total of the three numbers shown to 15 or higher", $B_1$ be the event "total of first two is 10", $B_2$ be the event "total of first two is 11", $B_3$ be the event "total of first two is 12". We have
begin{align}
P(B_1) = 3/6^2\
P(B_2) = 2/6^2\
P(B_3) = 1/6^2
end{align}
If $B$ is the event "total of first two is at least 10", then $P(B_1|B)=1/2$, $P(B_2|B)=1/3$ and $P(B_3|B)=1/6$. Finally
begin{align}
P(A|B)&=P(A|B_1,B)P(B_1|B)+P(A|B_2,B)P(B_2|B)+P(A|B_3,B)P(B_3|B)\
&=1/3times1/2+1/2times1/3+2/3times1/6=4/9
end{align}
I think B1 be the event "total of first two is 10" P(B1) = 3/(6x6) = 3/36 ?
– Jan Jin
Nov 19 '18 at 20:43
yup that was a typo
– dynamic89
Nov 19 '18 at 21:13
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
Hint: I suggest a Probability Tree with total values then if it is 15 or more as the second branch. Calculate the probabilities individually. This should help clear any doubt you have with your answer.
add a comment |
Hint: I suggest a Probability Tree with total values then if it is 15 or more as the second branch. Calculate the probabilities individually. This should help clear any doubt you have with your answer.
add a comment |
Hint: I suggest a Probability Tree with total values then if it is 15 or more as the second branch. Calculate the probabilities individually. This should help clear any doubt you have with your answer.
Hint: I suggest a Probability Tree with total values then if it is 15 or more as the second branch. Calculate the probabilities individually. This should help clear any doubt you have with your answer.
answered Nov 19 '18 at 0:20
anuj1610
12
12
add a comment |
add a comment |
if you list all possible events is 16, over sample space 216 events. 16/216 = 2/27
D1 D2 D3
1 4 -> 6 => 5
2 4 -> 6 => 6
3 5 -> 5 => 5
4 5 -> 5 => 6
5 6 -> 4 => 5
6 6 -> 4 => 6
7 5 -> 6 => 4
8 5 -> 6 => 5
9 5 -> 6 => 6
10 6 -> 5 => 4
11 6 -> 5 => 5
12 6 -> 5 => 6
13 6 -> 6 => 3
14 6 -> 6 => 4
15 6 -> 6 => 5
16 6 -> 6 => 6
for people think use conditional probability, I think the wrong part is use probabilty 1/6 for two dice sum 10, applies to each event.
add a comment |
if you list all possible events is 16, over sample space 216 events. 16/216 = 2/27
D1 D2 D3
1 4 -> 6 => 5
2 4 -> 6 => 6
3 5 -> 5 => 5
4 5 -> 5 => 6
5 6 -> 4 => 5
6 6 -> 4 => 6
7 5 -> 6 => 4
8 5 -> 6 => 5
9 5 -> 6 => 6
10 6 -> 5 => 4
11 6 -> 5 => 5
12 6 -> 5 => 6
13 6 -> 6 => 3
14 6 -> 6 => 4
15 6 -> 6 => 5
16 6 -> 6 => 6
for people think use conditional probability, I think the wrong part is use probabilty 1/6 for two dice sum 10, applies to each event.
add a comment |
if you list all possible events is 16, over sample space 216 events. 16/216 = 2/27
D1 D2 D3
1 4 -> 6 => 5
2 4 -> 6 => 6
3 5 -> 5 => 5
4 5 -> 5 => 6
5 6 -> 4 => 5
6 6 -> 4 => 6
7 5 -> 6 => 4
8 5 -> 6 => 5
9 5 -> 6 => 6
10 6 -> 5 => 4
11 6 -> 5 => 5
12 6 -> 5 => 6
13 6 -> 6 => 3
14 6 -> 6 => 4
15 6 -> 6 => 5
16 6 -> 6 => 6
for people think use conditional probability, I think the wrong part is use probabilty 1/6 for two dice sum 10, applies to each event.
if you list all possible events is 16, over sample space 216 events. 16/216 = 2/27
D1 D2 D3
1 4 -> 6 => 5
2 4 -> 6 => 6
3 5 -> 5 => 5
4 5 -> 5 => 6
5 6 -> 4 => 5
6 6 -> 4 => 6
7 5 -> 6 => 4
8 5 -> 6 => 5
9 5 -> 6 => 6
10 6 -> 5 => 4
11 6 -> 5 => 5
12 6 -> 5 => 6
13 6 -> 6 => 3
14 6 -> 6 => 4
15 6 -> 6 => 5
16 6 -> 6 => 6
for people think use conditional probability, I think the wrong part is use probabilty 1/6 for two dice sum 10, applies to each event.
answered Nov 19 '18 at 20:33
Jan Jin
11
11
add a comment |
add a comment |
Let $A$ be the event "total of the three numbers shown to 15 or higher", $B_1$ be the event "total of first two is 10", $B_2$ be the event "total of first two is 11", $B_3$ be the event "total of first two is 12". We have
begin{align}
P(B_1) = 3/6^2\
P(B_2) = 2/6^2\
P(B_3) = 1/6^2
end{align}
If $B$ is the event "total of first two is at least 10", then $P(B_1|B)=1/2$, $P(B_2|B)=1/3$ and $P(B_3|B)=1/6$. Finally
begin{align}
P(A|B)&=P(A|B_1,B)P(B_1|B)+P(A|B_2,B)P(B_2|B)+P(A|B_3,B)P(B_3|B)\
&=1/3times1/2+1/2times1/3+2/3times1/6=4/9
end{align}
I think B1 be the event "total of first two is 10" P(B1) = 3/(6x6) = 3/36 ?
– Jan Jin
Nov 19 '18 at 20:43
yup that was a typo
– dynamic89
Nov 19 '18 at 21:13
add a comment |
Let $A$ be the event "total of the three numbers shown to 15 or higher", $B_1$ be the event "total of first two is 10", $B_2$ be the event "total of first two is 11", $B_3$ be the event "total of first two is 12". We have
begin{align}
P(B_1) = 3/6^2\
P(B_2) = 2/6^2\
P(B_3) = 1/6^2
end{align}
If $B$ is the event "total of first two is at least 10", then $P(B_1|B)=1/2$, $P(B_2|B)=1/3$ and $P(B_3|B)=1/6$. Finally
begin{align}
P(A|B)&=P(A|B_1,B)P(B_1|B)+P(A|B_2,B)P(B_2|B)+P(A|B_3,B)P(B_3|B)\
&=1/3times1/2+1/2times1/3+2/3times1/6=4/9
end{align}
I think B1 be the event "total of first two is 10" P(B1) = 3/(6x6) = 3/36 ?
– Jan Jin
Nov 19 '18 at 20:43
yup that was a typo
– dynamic89
Nov 19 '18 at 21:13
add a comment |
Let $A$ be the event "total of the three numbers shown to 15 or higher", $B_1$ be the event "total of first two is 10", $B_2$ be the event "total of first two is 11", $B_3$ be the event "total of first two is 12". We have
begin{align}
P(B_1) = 3/6^2\
P(B_2) = 2/6^2\
P(B_3) = 1/6^2
end{align}
If $B$ is the event "total of first two is at least 10", then $P(B_1|B)=1/2$, $P(B_2|B)=1/3$ and $P(B_3|B)=1/6$. Finally
begin{align}
P(A|B)&=P(A|B_1,B)P(B_1|B)+P(A|B_2,B)P(B_2|B)+P(A|B_3,B)P(B_3|B)\
&=1/3times1/2+1/2times1/3+2/3times1/6=4/9
end{align}
Let $A$ be the event "total of the three numbers shown to 15 or higher", $B_1$ be the event "total of first two is 10", $B_2$ be the event "total of first two is 11", $B_3$ be the event "total of first two is 12". We have
begin{align}
P(B_1) = 3/6^2\
P(B_2) = 2/6^2\
P(B_3) = 1/6^2
end{align}
If $B$ is the event "total of first two is at least 10", then $P(B_1|B)=1/2$, $P(B_2|B)=1/3$ and $P(B_3|B)=1/6$. Finally
begin{align}
P(A|B)&=P(A|B_1,B)P(B_1|B)+P(A|B_2,B)P(B_2|B)+P(A|B_3,B)P(B_3|B)\
&=1/3times1/2+1/2times1/3+2/3times1/6=4/9
end{align}
edited Nov 19 '18 at 21:13
answered Nov 19 '18 at 1:58
dynamic89
38418
38418
I think B1 be the event "total of first two is 10" P(B1) = 3/(6x6) = 3/36 ?
– Jan Jin
Nov 19 '18 at 20:43
yup that was a typo
– dynamic89
Nov 19 '18 at 21:13
add a comment |
I think B1 be the event "total of first two is 10" P(B1) = 3/(6x6) = 3/36 ?
– Jan Jin
Nov 19 '18 at 20:43
yup that was a typo
– dynamic89
Nov 19 '18 at 21:13
I think B1 be the event "total of first two is 10" P(B1) = 3/(6x6) = 3/36 ?
– Jan Jin
Nov 19 '18 at 20:43
I think B1 be the event "total of first two is 10" P(B1) = 3/(6x6) = 3/36 ?
– Jan Jin
Nov 19 '18 at 20:43
yup that was a typo
– dynamic89
Nov 19 '18 at 21:13
yup that was a typo
– dynamic89
Nov 19 '18 at 21:13
add a comment |
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1
For example, how did you get $frac 2{27}$? Could you sketch your method?
– lulu
Nov 19 '18 at 0:12
The answer must be at least $frac26$ since the third die being $5$ or $6$ would be sufficient in every case
– Henry
Nov 19 '18 at 0:13