Question

There are twelve signs of the zodiac. How many people must be present for there to be at least a 50% chance that two or more of them were born under the same sign

Answer 1

Answer:

5

Step-by-step explanation:

Given that each zodiac sign occupies 1/12 of a year.

Then the minimum number of persons for Y[all different signs] < 0.5,

The probability of at least two having the same sign is 1 minus the probability of all having different signs.

This can be represented as A [at least 2 person share the same sign] = 1 - Y[all different signs] must be > 0.5

Therefore we have 1 - 12/12 *11/12 * 10/12 *9/12 *8/12 = 0.38

This implies that the lowest number will be found to be 5

Hence, the correct answer is 5.