Probability Question GCSE

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

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 ?

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!!

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

Let's say the probability of getting a red is $r$, then the probability of getting a blue is $b$, green is $g$, 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 $r + b + g + \cdots = 1$. 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 $1 - r$.

In your case, $r = 1-3x$ so you do $1 - (1-3x) = \underbrace{1 - 1}_{=0} -- 3x = 3x$. We are not saying that $1 - 3x = 1$. We are saying that $1 - (1-3x) = 3x$.

@Zacken will probably explain a lot better!!

thank you I think I fully understand now

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

yup I repped him

I understand the 1-(1-3x) but I dont understand how u get 1-1 --3x Coz where did the extra minus in front of the 3x come from