Sasha Shasha
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#1
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#1
A triangular spinner has one red side, one blue side and one green side. The red side is weighted so
that the spinner is four times more likely to land on the red side than on the blue side. The green side
is weighted so that the spinner is three times more likely to land on the green side than on the blue
side.

(i) Show that the probability that the spinner lands on the blue side is
1/8
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Äries
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#2
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#2
P(Red)=4*P(Blue)
P(Green)=3*P(Blue)
P(Red)+P(Green)+P(Blue)=1
Solving, 8*P(Blue)=1
So P(Blue)=1/8
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Sasha Shasha
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#3
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(Original post by Äries)
P(Red)=4*P(Blue)
P(Green)=3*P(Blue)
P(Red)+P(Green)+P(Blue)=1
Solving, 8*P(Blue)=1
So P(Blue)=1/8
The spinner is spun 3 times. Find the probability that it lands on a different coloured side each time.
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Äries
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#4
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#4
P(Red)=1/2
P(Green)=3/8
So, P(All different colours in three trials)
=P(Red)*P(Green)*P(Blue)*3!
=1/2*3/8*1/8*6
=9/64
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Sasha Shasha
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#5
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#5
(Original post by Äries)
P(Red)=1/2
P(Green)=3/8
So, P(All different colours in three trials)
=P(Red)*P(Green)*P(Blue)*3!
=1/2*3/8*1/8*6
=9/64
I'm sorry but can you help me explain a little more deeply about it ?
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Äries
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#6
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#6
(Original post by Sasha Shasha)
I'm sorry but can you help me explain a little more deeply about it ?
All different colours in three trials should be one of each of red, green and blue. This is AND type, so you should use multiplication rule. Lastly, a “6” represents different orders of outcomes. They’re: RGB, RBG, GRB, GBR, BRG, BGR.
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