SOLUTION: There are 12 signs of the Zodiac: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces. Each sign corresponds to a different cale

Algebra ->  Probability-and-statistics -> SOLUTION: There are 12 signs of the Zodiac: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces. Each sign corresponds to a different cale      Log On


   



Question 1060351: There are 12 signs of the Zodiac: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces. Each sign corresponds to a different calendar period of approximately 1 month.
Assuming that a person is just as likely to be born under one sign as another, what is the probability that in a group of five people at least two of them were born under the sign of Aries?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
Find the probability of 0 or 1 person is born under the sign and subtract from 1.
The probability of none is (11/12)^5=0.647.
The probability of one is 5*(1/12)(11/12)^4=0.2942 (the 5 in front is the number of ways it can happen).
The probability of two or more is 1-(0.941)=0.059. ANSWER
-----------------
Can check with looking at 2
10*(1/12)^2(11/12)^3=0.053
------------and 3
10*(1/12)^3)(11/12)^2=0.005
------------ and 4
5*(1/12)^4)(11/12)=0.0002
and 5
(1/12)^5=0.000004
This will add to 0.059 if taken out to enough decimal places.