Find the probability

Question

If 6 out of 10 people have their birthday in the 4 months of the year between February and May inclusive,then What is the probability is the next person has also his or her birthday in this 4 months?

Answer 1

Selecting 4 months out of 12 months = 4/12

Now already 6 people we have taken

Among last 4 people we have to select 1 people=1/4

So probability is 4/12*1/4=1/12

Comments

why r u considering last 4 people?It is said in the question that the next person so it must be the 7th person so no need to multiply it by 1/4 as per my understanding.

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no i think she is right . because  what i have calculated is all 7 person to have there bday on required months . but they want only the next person ( which is among thoseperson ) . answer would be 1/12 only

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@Subhro we can any one position among 4 , So, 4C1=4 but 7th position(i.e. that 1 position) is fixed So, 1/4C1 = 1/4 could u put any more logic to prove it false ? As I am little bit confused if 1/4 required or not

Answer 2

i think

There are 12 months in a year

Now they want a child may have birthday between Feb to may (both inclusive)= Feb , march , april ,may = 4/12

Now if 6 person out of 10 have there bday within this month then 6/10

But now they want even next person (all 7 )must have there bday so it will be 7/10

therefore for all 7 person to have there bday bewteen month may to feb is 4/12*7/10=7/30