pulled out hats

IMO E

My rephrase of the question:

1/2n - 2 ≥ 0 ---> 1/2n >= 2 ---> n >=4. so the question should be

what is the probability that n>=4?

1)

6 numbers in the hat and they are integers
you can construct two sets

s1={1,1,1,1,1,1} the probability of n>=4 is 0
s2={4,4,4,4,4,4} the probability of n>=4 is 1

insufficient

2)

for every value of n in the hat 1<=n<=30

using the same sets we have different values for the probability so statement two is insufficient and combining 1 and 2 as well.

mikeCoolBoy wrote: My rephrase of the question:

1/2n - 2 &#8805; 0 ---> 1/2n >= 2 ---> n >=4. so the question should be

what is the probability that n>=4?

Are you sure n>=4?

If 1/2n >=2, then 1>=4n ==> n<=1/4

I assumed that the expression was (1/2)n - 2 >=0.
If the expression is 1/(2n) -2 >=0 then 1/(2n) >=2 --->1/n >= 4

what is the probability that 1/4>= n>0?

1) there are 6 numbers are all are integers
sufficient the probability is 0 because n cannot be <= 1/4 and > 0

2) for every number n in the hat 1<=n<= 30
sufficient the probability is also 0