If the probability of spinning an A on spinner 1 is 3/4 and the probability of spinning E on spinner 2 is 1/3, what is the probability of spinning at least one vowel?
Assuming that they only vowels are an A on spinner 1 and an E on spinner 2:
There are four possibilities:
spinner 1 = A and spinner 2 = E = (3/4) x (1/3) = ?
spinner 1 = A and spinner 2 = not E = (3/4) x (2/3) = ?
spinner 1 = not A and spinner 2 = E = (1/4) x (1/3) = ?
spinner 1 = not A and spinner 2 = not E = (1/4) x (2/3) = ??
If you add the answers to the three possibilities that have a '?', you will get the probaiblity of getting at least one vowel.
Assuming that they only vowels are an A on spinner 1 and an E on spinner 2:
There are four possibilities:
spinner 1 = A and spinner 2 = E = (3/4) x (1/3) = ?
spinner 1 = A and spinner 2 = not E = (3/4) x (2/3) = ?
spinner 1 = not A and spinner 2 = E = (1/4) x (1/3) = ?
spinner 1 = not A and spinner 2 = not E = (1/4) x (2/3) = ??
If you add the answers to the three possibilities that have a '?', you will get the probaiblity of getting at least one vowel.
Thanks Geno,
If the probability of spinning an A on spinner 1 is 3/4 and the probability of spinning E on spinner 2 is 1/3, what is the probability of spinning at least one vowel?
Geno's answer is really good and will work perfectly.
Here is another method
first I will assume that the only vowel on 1 is A so P(vowel on 1) = 3/4
and the only vowel on 2 is E so P(cowel on 2) = 1/3 (Geno made the same assumption)
I could add those together but if I did I would be counting the probability of getting 2 vowels twice
P(2 vowels) = 3/4*1/3 = 1/4
so
P(of spining at least one vowel ) = 34+13−14=12+13=56
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P(AorB)=P(A)+P(B)−P(AandB)
This is the 2 spinner outcomes. So how if you just add them up the cross over bit will be counted twice?