samin101
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Can someone help me with this question as it is due tmrw and i have no clue how to attempt it and get the answer.
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samin101
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This one
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username5205898
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Hmm..I think ive done that question before
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username5205898
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😴😴
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jamiecjx
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Find expressions for the chance of picking a red ball from each one of the bags after two blue balls have been taken from one bag and placed into the other.
Remember that the chance of picking a red ball from each of these bags is the same, so equate the expressions to each other.
What you have written down is correct so far, keep going!
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samin101
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(Original post by jamiecjx)
Find expressions for the chance of picking a red ball from each one of the bags after two blue balls have been taken from one bag and placed into the other.
Remember that the chance of picking a red ball from each of these bags is the same, so equate the expressions to each other.
What you have written down is correct so far, keep going!
So 30/n+2 = n/12
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jamiecjx
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(Original post by samin101)
So 30/n+2 = n/12
Remember the probability is \frac{number\ of\ red\ balls}{number\ of\ red\ and\ blue\ balls}, you just did \frac{number\ of\ red\ balls}{number\ of\ blue\ balls}

You should end up with something like this (hidden in spoiler so you can check)

Spoiler:
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\frac{n}{12+n}=\frac{30}{32+n}
Last edited by jamiecjx; 7 months ago
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samin101
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(Original post by jamiecjx)
Remember the probability is \frac{number\ of\ red\ balls}{number\ of\ red\ and\ blue\ balls}, you just did \frac{number\ of\ red\ balls}{number\ of\ blue\ balls}
So 30/n+32 = n/n+12
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samin101
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(Original post by jamiecjx)
Remember the probability is \frac{number\ of\ red\ balls}{number\ of\ red\ and\ blue\ balls}, you just did \frac{number\ of\ red\ balls}{number\ of\ blue\ balls}

You should end up with something like this (hidden in spoiler so you can check)

Spoiler:
Show
\frac{n}{12+n}=\frac{30}{32+n}
So what should i do next? Im really bad at maths 😂
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jamiecjx
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(Original post by samin101)
So 30/n+32 = n/n+12
Yep now solve for n, start by getting rid of the fractions. Multiply both sides by (n+32) and (n+12)

Something like this should come out of it.
Spoiler:
Show
n\left(32+n\right)=30\left(12+n)


You will end up with a quadratic equation, which has two answers. One of these answers will not make any sense, and will be discarded.
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samin101
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(Original post by jamiecjx)
Yep now solve for n, start by getting rid of the fractions. Multiply both sides by (n+32) and (n+12)

Something like this should come out of it.
Spoiler:
Show
n\left(32+n\right)=30\left(12+n)


You will end up with a quadratic equation, which has two answers. One of these answers will not make any sense, and will be discarded.
So n^2+2n-360=0 but then you cannot factorise them
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jamiecjx
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(Original post by samin101)
So n^2+2n-360=0 but then you cannot factorise them
You can actually factorise it, but if you can't think of a way, just use the quadratic formula to find the solutions.



Spoiler:
Show
\left(n-18\right)\left(n+20\right)=0

n=18\ or\ -20
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samin101
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(Original post by jamiecjx)
You can actually factorise it, but if you can't think of a way, just use the quadratic formula to find the solutions.



Spoiler:
Show
\left(n-18\right)\left(n+20\right)=0

[tex]n=18\ or\ -20[/text
Thank you so much. You have been such a great help
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jamiecjx
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(Original post by samin101)
Thank you so much. You have been such a great help
My pleasure
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samin101
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(Original post by jamiecjx)
My pleasure
Could you help with this question?
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jamiecjx
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(Original post by samin101)
Could you help with this question?
So for this question there are a lot of approaches you could do.
ngl, I don't really know what you wrote down here, so Imma just start again.

For convenience, call P\left(G_{A}\right)=\ x and P\left(G_{B}\right)=\ y

The hint tells you to set up two equations. Find ways to express the two statements in terms of x and y. Remember P\left(A\ and\ B\right)=P(A) \times P(B)
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