SOLUTION: Last one... 3 dice are tossed - what is probability a) only two 5s b) at least two 5s c)three 5s d) no 5s 1 five

SOLUTION: Last one... 3 dice are tossed - what is probability a) only two 5s b) at least two 5s c)three 5s d) no 5s 1 five - 1 dice = 1/5 right? what's next?

Question 177400: Last one...
3 dice are tossed - what is probability a) only two 5s b) at least two 5s c)three 5s d) no 5s
1 five - 1 dice = 1/5 right? what's next?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
3 dice are tossed -
what is probability
a) only two 5s
The probability of getting a 5 with one die is 1/6
P(two 5's on three dice) = 3C2(1/6)^2*(5/6) = 3*(7/6^3) = 0.097222...
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b) at least two 5s
P(at least 2) = P(2 5's) + P(3 5's) = 0.097222 + 3C3((1/6)^3 = 1*(1/216)
= 0.9768...
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c)three 5s
P( 3 5's) = 1/6^3 = 1/216 = 0.0046296..
-----------------------
d) no 5s
P( no 5's) = (5/6)^3 = 0.5787037..
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1 five - 1 dice = 1/6 But one five on 3 dice is not 1/5, it is
3C1(1/6)^1(5/6)^2 = 75/216 = 0.3472222
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Cheers,
Stan H.
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