# Probability Question GCSE

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Hi could someone explain to me how this answer is correct

Q2 If the probability of spinning red on a spinner is 1 – 3x, find the probability of spinning any colour except red.

answer = 3x but I don't understand how

thanks

Q2 If the probability of spinning red on a spinner is 1 – 3x, find the probability of spinning any colour except red.

answer = 3x but I don't understand how

thanks

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#2

The probability of 1 includes red and every other colour.

So if you do 1-Probability(Red), then the rest of the colours probability can be given.

1-(1-3x) =

1-1= 0

You have a "-" outside the bracket and inside the bracket. Two minuses make a plus. So --3x is 3x.

Therefore your answer is 3x

Hope I was clear enough, please ask more questions if I wasn't clear

So if you do 1-Probability(Red), then the rest of the colours probability can be given.

1-(1-3x) =

1-1= 0

You have a "-" outside the bracket and inside the bracket. Two minuses make a plus. So --3x is 3x.

Therefore your answer is 3x

Hope I was clear enough, please ask more questions if I wasn't clear

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(Original post by

The probability of 1 includes red and every other colour.

So if you do 1-Probability(Red), then the rest of the colours probability can be given.

1-(1-3x) =

1-1= 0

You have a "-" outside the bracket and inside the bracket. Two minuses make a plus. So --3x is 3x.

Therefore your answer is 3x

Hope I was clear enough, please ask more questions if I wasn't clear

**MezmorisedPotato**)The probability of 1 includes red and every other colour.

So if you do 1-Probability(Red), then the rest of the colours probability can be given.

1-(1-3x) =

1-1= 0

You have a "-" outside the bracket and inside the bracket. Two minuses make a plus. So --3x is 3x.

Therefore your answer is 3x

Hope I was clear enough, please ask more questions if I wasn't clear

so does that mean that 1-3x is equal to 1 ?

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#4

(Original post by

Still a bit lost if you do 1-(1-3x) and that is the same as 1-1

so does that mean that 1-3x is equal to 1 ?

**samaad1**)Still a bit lost if you do 1-(1-3x) and that is the same as 1-1

so does that mean that 1-3x is equal to 1 ?

So take 1-3x from the total probability which is 1.

1- (1-3x)

1-1 is 0.

Since the 1 has been sorted out, you only have the --3x left which is 3x. You got to work on the bracket in steps

Zacken will probably explain a lot better!!

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(Original post by

Ok so it's like this. When you do 1( which is the total probability of red and all colours) - probability of red, then you get the probability of the rest. You know red has a probability of 1-3x.

So take 1-3x from the total probability which is 1.

1- (1-3x)

1-1 is 0.

Since the 1 has been sorted out, you only have the --3x left which is 3x. You got to work on the bracket in steps

Zacken will probably explain a lot better!!

**MezmorisedPotato**)Ok so it's like this. When you do 1( which is the total probability of red and all colours) - probability of red, then you get the probability of the rest. You know red has a probability of 1-3x.

So take 1-3x from the total probability which is 1.

1- (1-3x)

1-1 is 0.

Since the 1 has been sorted out, you only have the --3x left which is 3x. You got to work on the bracket in steps

Zacken will probably explain a lot better!!

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#6

(Original post by

Hi could someone explain to me how this answer is correct

Q2 If the probability of spinning red on a spinner is 1 – 3x, find the probability of spinning any colour except red.

answer = 3x but I don't understand how

thanks

**samaad1**)Hi could someone explain to me how this answer is correct

Q2 If the probability of spinning red on a spinner is 1 – 3x, find the probability of spinning any colour except red.

answer = 3x but I don't understand how

thanks

**some**colour. So the probability that you get a colour is 1. But that's the same as saying that the sum of the probabilites of getting red, green, blue, etc.. add up to 1.

So . Now, for you not to get a red means that you must get a blue or green or yellow or whatvever. Which is the probability of getting one of every single colour minus the probability of getting a red.

So since the probability of getting any colour is 1, then you subtract the probability of getting a red to get the probability of

**not**getting a red. This is .

In your case, so you do . We are

**not**saying that . We are saying that .

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(Original post by

Let's say the probability of getting a red is , then the probability of getting a blue is , green is , etc... do the same for every single colour. Now you know that you spinning the spinner means you must land on

So . Now, for you not to get a red means that you must get a blue or green or yellow or whatvever. Which is the probability of getting one of every single colour minus the probability of getting a red.

So since the probability of getting any colour is 1, then you subtract the probability of getting a red to get the probability of

In your case, so you do . We are

**Zacken**)Let's say the probability of getting a red is , then the probability of getting a blue is , green is , etc... do the same for every single colour. Now you know that you spinning the spinner means you must land on

**some**colour. So the probability that you get a colour is 1. But that's the same as saying that the sum of the probabilites of getting red, green, blue, etc.. add up to 1.So . Now, for you not to get a red means that you must get a blue or green or yellow or whatvever. Which is the probability of getting one of every single colour minus the probability of getting a red.

So since the probability of getting any colour is 1, then you subtract the probability of getting a red to get the probability of

**not**getting a red. This is .In your case, so you do . We are

**not**saying that . We are saying that .
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#8

(Original post by

thank you I think I fully understand now

**samaad1**)thank you I think I fully understand now

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(Original post by

No problem, give MezmorisedPotato his fair share of credit as well

**Zacken**)No problem, give MezmorisedPotato his fair share of credit as well

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