chetan2u
If Set A consists of 10 numbers, each number reciprocal of a prime number. Is the median of the Set A > 1/5?1) There are atleast 5 different numbers in the Set.
2) No number is used more than 2 times in the set.
Hi,
Lets see first the info provided by the Q
1) Set has 10 numbers.
2) each is a reciprocal of a prime number. so each is a fraction of form : 1/2,1/3,1/5...
3) Median for this set will depend on 5th and 6th numbers in the ascending/descending order.
lets see the statements..
1) There are atleast 5 different numbers in the Set.the numbers could be 1/2,1/2,1/2,1/2,1/3,1/3,1/5,1/7,1/7,1/11... median = 1/3.. >1/5 YES
the numbers could be 1/2,1/3,1/5,1/7,1/7,1/7,1/7,1/7,1/7,1/11... median = 1/7.. >1/5 NO..
we get two different answers .. insuff
2) No number is used more than 2 times in the set.We now know that each number can be written only twice..
since we are looking for 'larger', so lets test for the best possible case for largest number possible..best case will be when biggest number are used twice..
It will be reciprocal of smallest number 2,3,5,7,11..
so largest possible numbers in the set is\(\frac{1}{2},\frac{1}{2},\frac{1}{3},\frac{1}{3},\frac{1}{5},\frac{1}{5},\frac{1}{7},\frac{1}{7},\frac{1}{11},\frac{1}{11}\)..
median =1/5..
so largest possible median = 1/5, which is not > 1/5..answer will always be NO
Sufficient..
ans B