Countdown wrote:
Which of the following could be the median of a set consisting of 6 different primes?
(A) 2 (B) 3 (C) 9.5 (D) 12.5 (E) 39
Can somebody plz explain how to proceed.
Thanks in advance.
let the consecutive primes be a,b,c,d,e,f
So the median will be (c+d)/2
Looking
options we have to find 2*(any options) as sum of two consecutive primes.
becoz median here is avg. of two primes.
1) 2 (ie 2*2=4) so 4 cannot be the sum of middle two primes in a set of six consecutive primes.
2) 3 (3*2=6) same as option 1.
3)9.5(2*9.5=19) so sum can be 17+2 but 17 and 2 were not consecutive.
4)12.5 (2*12.5=25) same as option 3 ie we cannot find any two consecutive primes adding to 25.
5)39 (2*39=78) so here we find 78=37+41 are the two consecutive primes so the set is{29,31,37,41,43,47}
so E is our ans.