a set of 24 cards in numbered with the positive integers from 1 to 24. if the cards are shuffled and if only one is selected at random, what is the probability that the number on the card is divisible by 4 or 6?

Question

mathmate · Answer

How many of the numbers between 1 and 24 are divisible by 4 or by 6?
Divide this by the size of the sample space (24) to get the probability.

anonymous · Answer

divided by 4 are 4,8,12,16,20,24
                 6 are 6,12,18,24
10/24=5/12
is it correct??

anonymous · Answer

@mathmate

raden · Answer

the question is little ambigu,which one the correct :
divisible by 4 or divisible by 6 ? or
divisible by 4 or  6 ? --> we knowed that the number of 6 only once here

ganeshie8 · Answer

haha true its ambiguous ^

ganeshie8 · Answer

divided by 4 are 4,8,12,16,20,24
                 6 are 6,12,18,24
10/24=5/12
is it correct??

ganeshie8 · Answer

@dinisha  - careful, there are some common numbers between the two sets

ganeshie8 · Answer

divided by 4 are 4,8, `12`,16,20, `24`
                 6 are 6, `12`,18, `24`

mathmate · Answer

I think the 'OR' is just the normal interpretation, not the exclusive or.
It would otherwise have been qualified as "but not both".

anonymous · Answer

oh so when there is repeatition it is only count once? @ganeshie8

ganeshie8 · Answer

Exactly !

ganeshie8 · Answer

P(divisible by 4)  = 6/24
P(divisible by 6) = 4/24
P(divisible by 4 and 6) = 2/24

So, P(divisible by 4 or 6)  = 6/24 + 4/24 - 2/24
                                       =  8/24
                                       = 1/3

anonymous · Answer

thank you.. i am clear now!!

ganeshie8 · Answer

good :)