Question 753422: Lisa has 9 rings in her jewelry box. 5 are gold and 4 are silver. If she randomly selects 3 rings to wear to a party,find each probability.
14. P ( all gold or all silver)
and 16: P( at least 1 silver)
Can you show me the steps to complete this?
Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! Lisa has 9 rings in her jewelry box. 5 are gold and 4 are silver. If she randomly selects 3 rings to wear to a party,find each probability.
14. P ( all gold or all silver)
and 16: P( at least 1 silver)
14) what is P for all gold or all silver
P for all gold
first ring is gold, P is 5/9
second ring is gold, P is 4/8
third ring is gold, P is 3/7
P for all gold is (5/9)*(4/8)*(3/7)=.12 or 12%
P for all silver
first ring is silver, P is 4/9
second ring is silver, P is 3/8
third ring is silver, P is 2/7
P for all silver is (4/9)*(3/8)*(2/7)=.05 or 5%
16) P at least 1 is silver has the following possibilities, note that the probability of 1 silver is 4/9 and probability of 1 gold is 5/9
SGG = (4/9)(5/9)^2 = .14
GSG = (5/9)^2(4/9) = .14
GGS = (5/9)^2(4/9) = .14
SSG = (4/9)^2(5/9) = .11
SGS = (4/9)^2(5/9) = .11
GSS = (4/9)^2(5/9) = .11
SSS = (4/9)^3 = .09
now add all 7 probabilities and our answer is .84 or 84%
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