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Oh thank you so much vanillaRice!
Sorry for the confusion but I meant it in a different situation however which was for this question attached.

In a class of 24 students, 13 like mathematics, 9 like English and 3 like both.
Find the probability that a randomly selected student in this class likes neither Mathematics nor English.

I know that the answer was 5/24 but I just wanted to know how it would be done using the additional rule in probability out of curiosity.
Thank you so much VanillaRice for all the questions you've answered!
I really appreciate it and it helps me a lot!
 

So you can use the formula Pr(A U B) = Pr(A) + Pr(B) - Pr(A n B)
Pr(A U B) = 13 + 9 - 3
= 19
So everything outside the union is 5, or likes neither which is 5/24

[Phoenix11]

OK.
Thank you so much for all your help!
😊😊😊

[Phoenix11]

Hello .
I was so seeing if anyone could represent this question in a Venn diagram because I'm a bit confused.

The probability of rain ob any particular day is 0.2. However the probability of rain on a day after a rainy day is 0.85, whereas the probability of rain on a day after a non-rainy day is 0.1.

Thank you so much.

[Shadowxo]

Hello .
I was so seeing if anyone could represent this question in a Venn diagram because I'm a bit confused.

The probability of rain ob any particular day is 0.2. However the probability of rain on a day after a rainy day is 0.85, whereas the probability of rain on a day after a non-rainy day is 0.1.

Thank you so much.

That's more of a tree diagram question than a venn diagram question. Try using a tree diagram instead
Since the probabilities change, a venn diagram won't work.

[Phoenix11]

Oh sorry i meant tree diagram as that's what the chapter is about.
Sorry about that!

[Phoenix11]

However I still don't know how to do it with a tree diagram as I tried but I am a bit confused.

[Shadowxo]

However I still don't know how to do it with a tree diagram as I tried but I am a bit confused.

It says "The probability of rain on any particular day is 0.2" so start off with this. Create one branch with "rain" (I recommend using R) and probability 0.2. The other branch will therefore have "not rain" (NR) with probability 0.8.
From there, you should know the rest of the probabilities. For the Rain branch, you know the probability of rain on the next day is 0.85, and not rain is hence 0.15 ("The probability of rain on a day after a rainy day is 0.85"). For the Not Rain branch, use the same logic using the numbers for when the day before didn't rain (using "The probability of rain on a day after a non-rainy day is 0.1")

[Phoenix11]

Thank you so much! That really helped me get my head around it

I was wondering if anyone knew how to solve this question:
Two independent events,A and B,  are such that Pr(A)=0.4 and Pr(B)=0.3. Find:
Pr(AnB)
Thank you so much.

[VanillaRice]

Thank you so much! That really helped me get my head around it

I was wondering if anyone knew how to solve this question:
Two independent events,A and B,  are such that Pr(A)=0.4 and Pr(B)=0.3. Find:
Pr(AnB)
Thank you so much.

For any two independent events A and B,

So, your answer would be 0.4 x 0.3

[Phoenix11]

Ok
Thank you so much for the reply!
Could I ask how multiplying them gives the intersection?
Thank you.

[Phoenix11]

Never mind.
I understand
 

[VanillaRice]

Ok
Thank you so much for the reply!
Could I ask how multiplying them gives the intersection?
Thank you.

The best way I can think to explain this is to use an example. You are wanting both A and B to happen. Consider, the probability of flipping a coin and landing a heads (1/2) and the probability of rolling a 4 (1/6) on a standard 6-sided die. If you write out the entire sample space and circle all that satisfy heads on the coin and 4 on the die, you will see that you have circled 1/12 (= 1/2 x 1/6) of all the possibilities.

Hope this helps

[Phoenix11]

Thank you so much!
I understand it fully now!
😊😊

[Phoenix11]

Hello guys!
I was wondering if anyone knew the answer to this question and why it is that?
I actually don;t understand what the question is asking.
In order to conduct electricity, the substances must contain charged particles that can move around. Which type of substance contains charged particles that can always move around?
By the way, the substances that were being tested are:
Lead
Zinc
Potassium nitrate
Salt
Sugar
Wax
Deionised water

Thank you so much!
 

[Shadowxo]

Hello guys!
I was wondering if anyone knew the answer to this question and why it is that?
I actually don;t understand what the question is asking.
In order to conduct electricity, the substances must contain charged particles that can move around. Which type of substance contains charged particles that can always move around?
By the way, the substances that were being tested are:
Lead
Zinc
Potassium nitrate
Salt
Sugar
Wax
Deionised water

Thank you so much!
 

It's been a while, but to conduct electricity you need charged particles (ie positive or negatively charged particles) that can move around (so liquid or aqueous, or electrons free to move). Some substances dissolve in water to form + and - charged particles, this means they conduct electricity.
Eg lead is a metal so has electrons that can move around. It'll conduct electricity.
Eg potassium nitrate dissolves into K+ and NO3-, and can move around in water (soluble / aqueous) so does conduct electricity.
Edit: I was only thinking about materials that would result in water conducting electricity. Some answers will depend on the experiment (eg was it a big block of salt or was it dissolved in water? It'll conduct if dissolved in water but won't if it's just in a big block, as it won't be free to move)
Fixed accordingly